Merge pull request #3 from gilardh/master

paper librustzcash sync
Merge pull request #214 from ebfull/manifest-updates
2020-03-14 08:09:30 -07:00 · 2020-03-04 10:05:44 -07:00 · 2020-03-04 09:28:56 -07:00 · 2020-03-04 09:04:14 -07:00 · 2020-03-04 18:25:35 +13:00 · 2020-03-04 15:11:42 +13:00
152 changed files with 12409 additions and 9975 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,120 @@
 name: CI checks
 on: [push, pull_request]
 jobs:
  lint:
    name: Lint
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1
      - uses: actions-rs/toolchain@v1
        with:
          toolchain: 1.37.0
          override: true
      # cargo fmt does not build the code, and running it in a fresh clone of
      # the codebase will fail because the protobuf code has not been generated.
      - name: cargo build
        uses: actions-rs/cargo@v1
        with:
          command: build
          args: --all
      # Ensure all code has been formatted with rustfmt
      - run: rustup component add rustfmt
      - name: Check formatting
        uses: actions-rs/cargo@v1
        with:
          command: fmt
          args: --all -- --check --color always
  test:
    name: Test on ${{ matrix.os }}
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest, macOS-latest]
    steps:
      - uses: actions/checkout@v1
      - uses: actions-rs/toolchain@v1
        with:
          toolchain: 1.37.0
          override: true
      - name: cargo fetch
        uses: actions-rs/cargo@v1
        with:
          command: fetch
      - name: Build tests
        uses: actions-rs/cargo@v1
        with:
          command: build
          args: --verbose --release --all --tests
      - name: Run tests
        uses: actions-rs/cargo@v1
        with:
          command: test
          args: --verbose --release --all
      - name: Run slow tests
        uses: actions-rs/cargo@v1
        with:
          command: test
          args: --verbose --release --all -- --ignored
  codecov:
    name: Code coverage
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1
      # Use stable for this to ensure that cargo-tarpaulin can be built.
      - uses: actions-rs/toolchain@v1
        with:
          toolchain: stable
          override: true
      - name: Install cargo-tarpaulin
        uses: actions-rs/cargo@v1
        with:
          command: install
          args: cargo-tarpaulin
      - name: Generate coverage report
        uses: actions-rs/cargo@v1
        with:
          command: tarpaulin
          args: --release --timeout 600 --out Xml --packages "librustzcash,zcash_client_backend,zcash_primitives,zcash_proofs"
      - name: Upload coverage to Codecov
        uses: codecov/codecov-action@v1.0.3
        with:
          token: ${{secrets.CODECOV_TOKEN}}
  doc-links:
    name: Nightly lint
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1
      - uses: actions-rs/toolchain@v1
        with:
          toolchain: nightly
          override: true
      - name: cargo fetch
        uses: actions-rs/cargo@v1
        with:
          command: fetch
      # Ensure intra-documentation links all resolve correctly
      # Requires #![deny(intra_doc_link_resolution_failure)] in crates.
      - name: Check intra-doc links
        uses: actions-rs/cargo@v1
        with:
          command: doc
          args: --all --document-private-items
      # Build benchmarks to prevent bitrot
      - name: Build benchmarks
        uses: actions-rs/cargo@v1
        with:
          command: build
          args: --verbose --all --benches
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,6 @@
 language: rust
 rust:
-  - 1.36.0
+  - 1.37.0
 cache: cargo
@@ -11,3 +11,9 @@ script:
  - cargo build --verbose --release --all
  - cargo fmt --all -- --check
  - cargo test --verbose --release --all
  - cargo test --verbose --release --all -- --ignored
 before_cache:
  - rm -rf "$TRAVIS_HOME/.cargo/registry/src"
  - cargo install cargo-update || echo "cargo-update already installed"
  - cargo install-update -a # update outdated cached binaries
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -29,6 +29,14 @@ dependencies = [
 "opaque-debug 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "aho-corasick"
 version = "0.7.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "arrayref"
 version = "0.3.5"
@@ -42,6 +50,11 @@ dependencies = [
 "nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "assert_matches"
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "autocfg"
 version = "0.1.6"
@@ -54,25 +67,34 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "bellman"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
 "bit-vec 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
 "blake2s_simd 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "ff 0.4.0",
+ "ff 0.5.2",
 "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
 "futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "group 0.1.0",
+ "group 0.2.0",
- "hex-literal 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "pairing 0.14.2",
+ "pairing 0.15.1",
 "rand 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_xorshift 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "bigint"
 version = "4.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "crunchy 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "bit-vec"
 version = "0.4.4"
@@ -80,7 +102,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "bitflags"
-version = "1.1.0"
+version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
@@ -130,14 +152,6 @@ dependencies = [
 "byte-tools 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "bs58"
 version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "byte-tools"
 version = "0.3.1"
@@ -159,7 +173,7 @@ dependencies = [
 [[package]]
 name = "cc"
-version = "1.0.42"
+version = "1.0.45"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
@@ -167,6 +181,14 @@ name = "cfg-if"
 version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "cloudabi"
 version = "0.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "constant_time_eq"
 version = "0.1.4"
@@ -174,7 +196,67 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "crossbeam"
-version = "0.3.2"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-channel 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-deque 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-epoch 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-queue 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "crossbeam-channel"
 version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "crossbeam-deque"
 version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "crossbeam-epoch 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "crossbeam-epoch"
 version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "arrayvec 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
 "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "memoffset 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "scopeguard 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "crossbeam-queue"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "crossbeam-utils"
 version = "0.6.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "crunchy"
 version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
@@ -207,40 +289,39 @@ dependencies = [
 "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "env_logger"
 version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "fake-simd"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "fallible-iterator"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "fallible-streaming-iterator"
 version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "ff"
-version = "0.4.0"
+version = "0.5.2"
 dependencies = [
 "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "ff_derive 0.3.0",
+ "ff_derive 0.4.1",
 "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "ff_derive"
-version = "0.3.0"
+version = "0.4.1"
 dependencies = [
 "num-bigint 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "num-integer 0.1.41 (registry+https://github.com/rust-lang/crates.io-index)",
 "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@@ -255,6 +336,11 @@ dependencies = [
 "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "fuchsia-cprng"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "futures"
 version = "0.1.29"
@@ -279,19 +365,19 @@ dependencies = [
 [[package]]
 name = "getrandom"
-version = "0.1.11"
+version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
- "wasi 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "group"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
- "ff 0.4.0",
+ "ff 0.5.2",
 "rand 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_xorshift 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -303,19 +389,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "hex-literal"
-version = "0.1.4"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "hex-literal-impl 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hex-literal-impl 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro-hack 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "hex-literal-impl"
-version = "0.1.2"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro-hack 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@@ -330,50 +416,42 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "librustzcash"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
- "bellman 0.1.0",
+ "bellman 0.2.0",
 "blake2b_simd 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "blake2s_simd 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ff 0.5.2",
 "ff 0.4.0",
 "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
- "pairing 0.14.2",
+ "pairing 0.15.1",
 "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_os 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "zcash_history 0.0.1",
- "zcash_primitives 0.0.0",
+ "zcash_primitives 0.1.0",
- "zcash_proofs 0.0.0",
+ "zcash_proofs 0.1.0",
 ]
 [[package]]
-name = "libsqlite3-sys"
+name = "log"
-version = "0.16.0"
+version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cc 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "pkg-config 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "vcpkg 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "linked-hash-map"
 version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "lru-cache"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "memchr"
-version = "2.2.1"
+version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "memoffset"
 version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "nodrop"
 version = "0.1.13"
@@ -421,20 +499,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "pairing"
-version = "0.14.2"
+version = "0.15.1"
 dependencies = [
 "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "ff 0.4.0",
+ "ff 0.5.2",
- "group 0.1.0",
+ "group 0.2.0",
 "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_xorshift 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "pkg-config"
 version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "ppv-lite86"
 version = "0.2.5"
@@ -442,53 +515,79 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "proc-macro-hack"
-version = "0.4.2"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro-hack-impl 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "proc-macro-hack-impl"
 version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "proc-macro2"
-version = "0.4.30"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "protobuf"
-version = "2.8.0"
+version = "2.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "protobuf-codegen"
-version = "2.8.0"
+version = "2.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "protobuf 2.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "protobuf 2.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "protobuf-codegen-pure"
-version = "2.8.0"
+version = "2.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "protobuf 2.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "protobuf 2.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "protobuf-codegen 2.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "protobuf-codegen 2.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "quickcheck"
 version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "quote"
-version = "0.6.13"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "rand"
 version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "autocfg 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
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--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ members = [
    "librustzcash",
    "pairing",
    "zcash_client_backend",
-    "zcash_client_sqlite",
+    "zcash_history",
    "zcash_primitives",
    "zcash_proofs",
 ]
--- a/bellman/Cargo.toml
+++ b/bellman/Cargo.toml
@@ -1,28 +1,29 @@
 [package]
 authors = ["Sean Bowe <ewillbefull@gmail.com>"]
 description = "zk-SNARK library"
-documentation = "https://github.com/ebfull/bellman"
+readme = "README.md"
 homepage = "https://github.com/ebfull/bellman"
 license = "MIT/Apache-2.0"
 name = "bellman"
 repository = "https://github.com/ebfull/bellman"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2018"
 [dependencies]
 bit-vec = "0.4.4"
 blake2s_simd = "0.5"
-ff = { path = "../ff" }
+ff = { version = "0.5.0", path = "../ff" }
 futures = "0.1"
 futures-cpupool = { version = "0.1", optional = true }
-group = { path = "../group" }
+group = { version = "0.2.0", path = "../group" }
 num_cpus = { version = "1", optional = true }
-crossbeam = { version = "0.3", optional = true }
+crossbeam = { version = "0.7", optional = true }
-pairing = { path = "../pairing", optional = true }
+pairing = { version = "0.15.0", path = "../pairing", optional = true }
 rand_core = "0.5"
 byteorder = "1"
 [dev-dependencies]
-hex-literal = "0.1"
+hex-literal = "0.2"
 rand = "0.7"
 rand_xorshift = "0.2"
 sha2 = "0.8"
@@ -36,3 +37,6 @@ default = ["groth16", "multicore"]
 name = "mimc"
 path = "tests/mimc.rs"
 required-features = ["groth16"]
 [badges]
 maintenance = { status = "actively-developed" }
--- a/bellman/README.md
+++ b/bellman/README.md
@@ -1,12 +1,23 @@
 # bellman [![Crates.io](https://img.shields.io/crates/v/bellman.svg)](https://crates.io/crates/bellman) #
-This is a research project being built for [Zcash](https://z.cash/).
+`bellman` is a crate for building zk-SNARK circuits. It provides circuit traits
 and primitive structures, as well as basic gadget implementations such as
 booleans and number abstractions.
 ## Roadmap
 `bellman` is being refactored into a generic proving library. Currently it is
 pairing-specific, and different types of proving systems need to be implemented
 as sub-modules. After the refactor, `bellman` will be generic using the `ff` and
 `group` crates, while specific proving systems will be separate crates that pull
 in the dependencies they require.
 ## License
 Licensed under either of
- * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
--- a/bellman/src/domain.rs
+++ b/bellman/src/domain.rs
@@ -1,14 +1,15 @@
-//! This module contains an `EvaluationDomain` abstraction for
+//! This module contains an [`EvaluationDomain`] abstraction for performing
-//! performing various kinds of polynomial arithmetic on top of
+//! various kinds of polynomial arithmetic on top of the scalar field.
 //! the scalar field.
 //!
-//! In pairing-based SNARKs like Groth16, we need to calculate
+//! In pairing-based SNARKs like [Groth16], we need to calculate a quotient
-//! a quotient polynomial over a target polynomial with roots
+//! polynomial over a target polynomial with roots at distinct points associated
-//! at distinct points associated with each constraint of the
+//! with each constraint of the constraint system. In order to be efficient, we
-//! constraint system. In order to be efficient, we choose these
+//! choose these roots to be the powers of a 2<sup>n</sup> root of unity in the
-//! roots to be the powers of a 2^n root of unity in the field.
+//! field. This allows us to perform polynomial operations in O(n) by performing
-//! This allows us to perform polynomial operations in O(n)
+//! an O(n log n) FFT over such a domain.
-//! by performing an O(n log n) FFT over such a domain.
+//!
 //! [`EvaluationDomain`]: crate::domain::EvaluationDomain
 //! [Groth16]: https://eprint.iacr.org/2016/260
 use ff::{Field, PrimeField, ScalarEngine};
 use group::CurveProjective;
@@ -26,15 +27,19 @@ pub struct EvaluationDomain<E: ScalarEngine, G: Group<E>> {
    minv: E::Fr,
 }
-impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
+impl<E: ScalarEngine, G: Group<E>> AsRef<[G]> for EvaluationDomain<E, G> {
-    pub fn as_ref(&self) -> &[G] {
+    fn as_ref(&self) -> &[G] {
        &self.coeffs
    }
 }
-    pub fn as_mut(&mut self) -> &mut [G] {
+impl<E: ScalarEngine, G: Group<E>> AsMut<[G]> for EvaluationDomain<E, G> {
    fn as_mut(&mut self) -> &mut [G] {
        &mut self.coeffs
    }
 }
 impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
    pub fn into_coeffs(self) -> Vec<G> {
        self.coeffs
    }
@@ -64,9 +69,9 @@ impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
        coeffs.resize(m, G::group_zero());
        Ok(EvaluationDomain {
-            coeffs: coeffs,
+            coeffs,
-            exp: exp,
+            exp,
-            omega: omega,
+            omega,
            omegainv: omega.inverse().unwrap(),
            geninv: E::Fr::multiplicative_generator().inverse().unwrap(),
            minv: E::Fr::from_str(&format!("{}", m))
@@ -87,7 +92,7 @@ impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
            let minv = self.minv;
            for v in self.coeffs.chunks_mut(chunk) {
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    for v in v {
                        v.group_mul_assign(&minv);
                    }
@@ -99,7 +104,7 @@ impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
    pub fn distribute_powers(&mut self, worker: &Worker, g: E::Fr) {
        worker.scope(self.coeffs.len(), |scope, chunk| {
            for (i, v) in self.coeffs.chunks_mut(chunk).enumerate() {
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    let mut u = g.pow(&[(i * chunk) as u64]);
                    for v in v.iter_mut() {
                        v.group_mul_assign(&u);
@@ -142,7 +147,7 @@ impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
        worker.scope(self.coeffs.len(), |scope, chunk| {
            for v in self.coeffs.chunks_mut(chunk) {
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    for v in v {
                        v.group_mul_assign(&i);
                    }
@@ -161,7 +166,7 @@ impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
                .chunks_mut(chunk)
                .zip(other.coeffs.chunks(chunk))
            {
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    for (a, b) in a.iter_mut().zip(b.iter()) {
                        a.group_mul_assign(&b.0);
                    }
@@ -180,7 +185,7 @@ impl<E: ScalarEngine, G: Group<E>> EvaluationDomain<E, G> {
                .chunks_mut(chunk)
                .zip(other.coeffs.chunks(chunk))
            {
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    for (a, b) in a.iter_mut().zip(b.iter()) {
                        a.group_sub_assign(&b);
                    }
@@ -291,7 +296,7 @@ fn serial_fft<E: ScalarEngine, T: Group<E>>(a: &mut [T], omega: &E::Fr, log_n: u
    let mut m = 1;
    for _ in 0..log_n {
-        let w_m = omega.pow(&[(n / (2 * m)) as u64]);
+        let w_m = omega.pow(&[u64::from(n / (2 * m))]);
        let mut k = 0;
        while k < n {
@@ -331,18 +336,18 @@ fn parallel_fft<E: ScalarEngine, T: Group<E>>(
        let a = &*a;
        for (j, tmp) in tmp.iter_mut().enumerate() {
-            scope.spawn(move || {
+            scope.spawn(move |_scope| {
                // Shuffle into a sub-FFT
                let omega_j = omega.pow(&[j as u64]);
                let omega_step = omega.pow(&[(j as u64) << log_new_n]);
                let mut elt = E::Fr::one();
-                for i in 0..(1 << log_new_n) {
+                for (i, tmp) in tmp.iter_mut().enumerate() {
                    for s in 0..num_cpus {
                        let idx = (i + (s << log_new_n)) % (1 << log_n);
                        let mut t = a[idx];
                        t.group_mul_assign(&elt);
-                        tmp[i].group_add_assign(&t);
+                        tmp.group_add_assign(&t);
                        elt.mul_assign(&omega_step);
                    }
                    elt.mul_assign(&omega_j);
@@ -359,7 +364,7 @@ fn parallel_fft<E: ScalarEngine, T: Group<E>>(
        let tmp = &tmp;
        for (idx, a) in a.chunks_mut(chunk).enumerate() {
-            scope.spawn(move || {
+            scope.spawn(move |_scope| {
                let mut idx = idx * chunk;
                let mask = (1 << log_cpus) - 1;
                for a in a {
--- a/bellman/src/gadgets.rs
+++ b/bellman/src/gadgets.rs
@@ -1,3 +1,5 @@
 //! Self-contained sub-circuit implementations for various primitives.
 pub mod test;
 pub mod blake2s;
--- a/bellman/src/gadgets/blake2s.rs
+++ b/bellman/src/gadgets/blake2s.rs
@@ -1,12 +1,10 @@
-use pairing::Engine;
+//! The [BLAKE2s] hash function with personalization support.
 //!
 //! [BLAKE2s]: https://tools.ietf.org/html/rfc7693
 use super::{boolean::Boolean, multieq::MultiEq, uint32::UInt32};
 use crate::{ConstraintSystem, SynthesisError};
-
+use ff::ScalarEngine;
 use super::boolean::Boolean;
 use super::uint32::UInt32;
 use super::multieq::MultiEq;
 /*
 2.1.  Parameters
@@ -81,7 +79,7 @@ const SIGMA: [[usize; 16]; 10] = [
       END FUNCTION.
 */
-fn mixing_g<E: Engine, CS: ConstraintSystem<E>, M>(
+fn mixing_g<E: ScalarEngine, CS: ConstraintSystem<E>, M>(
    mut cs: M,
    v: &mut [UInt32],
    a: usize,
@@ -166,7 +164,7 @@ where
       END FUNCTION.
 */
-fn blake2s_compression<E: Engine, CS: ConstraintSystem<E>>(
+fn blake2s_compression<E: ScalarEngine, CS: ConstraintSystem<E>>(
    mut cs: CS,
    h: &mut [UInt32],
    m: &[UInt32],
@@ -339,7 +337,7 @@ fn blake2s_compression<E: Engine, CS: ConstraintSystem<E>>(
        END FUNCTION.
 */
-pub fn blake2s<E: Engine, CS: ConstraintSystem<E>>(
+pub fn blake2s<E: ScalarEngine, CS: ConstraintSystem<E>>(
    mut cs: CS,
    input: &[Boolean],
    personalization: &[u8],
@@ -382,7 +380,7 @@ pub fn blake2s<E: Engine, CS: ConstraintSystem<E>>(
        blocks.push(this_block);
    }
-    if blocks.len() == 0 {
+    if blocks.is_empty() {
        blocks.push((0..16).map(|_| UInt32::constant(0)).collect());
    }
@@ -404,12 +402,13 @@ pub fn blake2s<E: Engine, CS: ConstraintSystem<E>>(
        )?;
    }
-    Ok(h.iter().flat_map(|b| b.into_bits()).collect())
+    Ok(h.into_iter().flat_map(|b| b.into_bits()).collect())
 }
 #[cfg(test)]
 mod test {
    use blake2s_simd::Params as Blake2sParams;
    use hex_literal::hex;
    use pairing::bls12_381::Bls12;
    use rand_core::{RngCore, SeedableRng};
    use rand_xorshift::XorShiftRng;
@@ -433,7 +432,7 @@ mod test {
        let expected = hex!("c59f682376d137f3f255e671e207d1f2374ebe504e9314208a52d9f88d69e8c8");
        let mut out = out.into_iter();
-        for b in expected.into_iter() {
+        for b in expected.iter() {
            for i in 0..8 {
                let c = out.next().unwrap().get_value().unwrap();
@@ -554,4 +553,145 @@ mod test {
            }
        }
    }
    #[test]
    fn test_blake2s_256_vars() {
        let data: Vec<u8> = hex!("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").to_vec();
        assert_eq!(data.len(), 256);
        let mut cs = TestConstraintSystem::<Bls12>::new();
        let mut input_bits = vec![];
        for (byte_i, input_byte) in data.into_iter().enumerate() {
            for bit_i in 0..8 {
                let cs = cs.namespace(|| format!("input bit {} {}", byte_i, bit_i));
                input_bits.push(
                    AllocatedBit::alloc(cs, Some((input_byte >> bit_i) & 1u8 == 1u8))
                        .unwrap()
                        .into(),
                );
            }
        }
        let r = blake2s(&mut cs, &input_bits, b"12345678").unwrap();
        assert!(cs.is_satisfied());
        let expected = hex!("0af5695115ced92c8a0341e43869209636e9aa6472e4576f0f2b996cf812b30e");
        let mut out = r.into_iter();
        for b in expected.iter() {
            for i in 0..8 {
                let c = out.next().unwrap().get_value().unwrap();
                assert_eq!(c, (b >> i) & 1u8 == 1u8);
            }
        }
    }
    #[test]
    fn test_blake2s_700_vars() {
        let data: Vec<u8> = hex!("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").to_vec();
        assert_eq!(data.len(), 700);
        let mut cs = TestConstraintSystem::<Bls12>::new();
        let mut input_bits = vec![];
        for (byte_i, input_byte) in data.into_iter().enumerate() {
            for bit_i in 0..8 {
                let cs = cs.namespace(|| format!("input bit {} {}", byte_i, bit_i));
                input_bits.push(
                    AllocatedBit::alloc(cs, Some((input_byte >> bit_i) & 1u8 == 1u8))
                        .unwrap()
                        .into(),
                );
            }
        }
        let r = blake2s(&mut cs, &input_bits, b"12345678").unwrap();
        assert!(cs.is_satisfied());
        let expected = hex!("2ab8f0683167ba220eef19dccf4f9b1a8193cc09b35e0235842323950530f18a");
        let mut out = r.into_iter();
        for b in expected.iter() {
            for i in 0..8 {
                let c = out.next().unwrap().get_value().unwrap();
                assert_eq!(c, (b >> i) & 1u8 == 1u8);
            }
        }
    }
    #[test]
    fn test_blake2s_test_vectors() {
        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let expecteds = [
            hex!("a1309e334376c8f36a736a4ab0e691ef931ee3ebdb9ea96187127136fea622a1"),
            hex!("82fefff60f265cea255252f7c194a7f93965dffee0609ef74eb67f0d76cd41c6"),
        ];
        for i in 0..2 {
            let mut h = Blake2sParams::new()
                .hash_length(32)
                .personal(b"12345678")
                .to_state();
            let input_len = 1024;
            let data: Vec<u8> = (0..input_len).map(|_| rng.next_u32() as u8).collect();
            h.update(&data);
            let hash_result = h.finalize();
            let mut cs = TestConstraintSystem::<Bls12>::new();
            let mut input_bits = vec![];
            for (byte_i, input_byte) in data.into_iter().enumerate() {
                for bit_i in 0..8 {
                    let cs = cs.namespace(|| format!("input bit {} {}", byte_i, bit_i));
                    input_bits.push(
                        AllocatedBit::alloc(cs, Some((input_byte >> bit_i) & 1u8 == 1u8))
                            .unwrap()
                            .into(),
                    );
                }
            }
            let r = blake2s(&mut cs, &input_bits, b"12345678").unwrap();
            assert!(cs.is_satisfied());
            let mut s = hash_result
                .as_ref()
                .iter()
                .flat_map(|&byte| (0..8).map(move |i| (byte >> i) & 1u8 == 1u8));
            for b in r {
                match b {
                    Boolean::Is(b) => {
                        assert!(s.next().unwrap() == b.get_value().unwrap());
                    }
                    Boolean::Not(b) => {
                        assert!(s.next().unwrap() != b.get_value().unwrap());
                    }
                    Boolean::Constant(b) => {
                        assert!(input_len == 0);
                        assert!(s.next().unwrap() == b);
                    }
                }
            }
            assert_eq!(expecteds[i], hash_result.as_bytes());
        }
    }
 }
--- a/bellman/src/gadgets/boolean.rs
+++ b/bellman/src/gadgets/boolean.rs
@@ -1,5 +1,6 @@
-use ff::{BitIterator, Field, PrimeField};
+//! Gadgets for allocating bits in the circuit and performing boolean logic.
-use pairing::Engine;
+
 use ff::{BitIterator, Field, PrimeField, ScalarEngine};
 use crate::{ConstraintSystem, LinearCombination, SynthesisError, Variable};
@@ -31,7 +32,7 @@ impl AllocatedBit {
        must_be_false: &AllocatedBit,
    ) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let var = cs.alloc(
@@ -60,7 +61,7 @@ impl AllocatedBit {
        Ok(AllocatedBit {
            variable: var,
-            value: value,
+            value,
        })
    }
@@ -68,7 +69,7 @@ impl AllocatedBit {
    /// boolean value.
    pub fn alloc<E, CS>(mut cs: CS, value: Option<bool>) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let var = cs.alloc(
@@ -93,7 +94,7 @@ impl AllocatedBit {
        Ok(AllocatedBit {
            variable: var,
-            value: value,
+            value,
        })
    }
@@ -101,7 +102,7 @@ impl AllocatedBit {
    /// an `AllocatedBit`.
    pub fn xor<E, CS>(mut cs: CS, a: &Self, b: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let mut result_value = None;
@@ -153,7 +154,7 @@ impl AllocatedBit {
    /// an `AllocatedBit`.
    pub fn and<E, CS>(mut cs: CS, a: &Self, b: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let mut result_value = None;
@@ -191,7 +192,7 @@ impl AllocatedBit {
    /// Calculates `a AND (NOT b)`.
    pub fn and_not<E, CS>(mut cs: CS, a: &Self, b: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let mut result_value = None;
@@ -229,7 +230,7 @@ impl AllocatedBit {
    /// Calculates `(NOT a) AND (NOT b)`.
    pub fn nor<E, CS>(mut cs: CS, a: &Self, b: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let mut result_value = None;
@@ -265,7 +266,7 @@ impl AllocatedBit {
    }
 }
-pub fn u64_into_boolean_vec_le<E: Engine, CS: ConstraintSystem<E>>(
+pub fn u64_into_boolean_vec_le<E: ScalarEngine, CS: ConstraintSystem<E>>(
    mut cs: CS,
    value: Option<u64>,
 ) -> Result<Vec<Boolean>, SynthesisError> {
@@ -296,16 +297,16 @@ pub fn u64_into_boolean_vec_le<E: Engine, CS: ConstraintSystem<E>>(
    Ok(bits)
 }
-pub fn field_into_boolean_vec_le<E: Engine, CS: ConstraintSystem<E>, F: PrimeField>(
+pub fn field_into_boolean_vec_le<E: ScalarEngine, CS: ConstraintSystem<E>, F: PrimeField>(
    cs: CS,
    value: Option<F>,
 ) -> Result<Vec<Boolean>, SynthesisError> {
    let v = field_into_allocated_bits_le::<E, CS, F>(cs, value)?;
-    Ok(v.into_iter().map(|e| Boolean::from(e)).collect())
+    Ok(v.into_iter().map(Boolean::from).collect())
 }
-pub fn field_into_allocated_bits_le<E: Engine, CS: ConstraintSystem<E>, F: PrimeField>(
+pub fn field_into_allocated_bits_le<E: ScalarEngine, CS: ConstraintSystem<E>, F: PrimeField>(
    mut cs: CS,
    value: Option<F>,
 ) -> Result<Vec<AllocatedBit>, SynthesisError> {
@@ -367,7 +368,7 @@ impl Boolean {
    pub fn enforce_equal<E, CS>(mut cs: CS, a: &Self, b: &Self) -> Result<(), SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        match (a, b) {
@@ -412,24 +413,24 @@ impl Boolean {
    }
    pub fn get_value(&self) -> Option<bool> {
-        match self {
+        match *self {
-            &Boolean::Constant(c) => Some(c),
+            Boolean::Constant(c) => Some(c),
-            &Boolean::Is(ref v) => v.get_value(),
+            Boolean::Is(ref v) => v.get_value(),
-            &Boolean::Not(ref v) => v.get_value().map(|b| !b),
+            Boolean::Not(ref v) => v.get_value().map(|b| !b),
        }
    }
-    pub fn lc<E: Engine>(&self, one: Variable, coeff: E::Fr) -> LinearCombination<E> {
+    pub fn lc<E: ScalarEngine>(&self, one: Variable, coeff: E::Fr) -> LinearCombination<E> {
-        match self {
+        match *self {
-            &Boolean::Constant(c) => {
+            Boolean::Constant(c) => {
                if c {
                    LinearCombination::<E>::zero() + (coeff, one)
                } else {
                    LinearCombination::<E>::zero()
                }
            }
-            &Boolean::Is(ref v) => LinearCombination::<E>::zero() + (coeff, v.get_variable()),
+            Boolean::Is(ref v) => LinearCombination::<E>::zero() + (coeff, v.get_variable()),
-            &Boolean::Not(ref v) => {
+            Boolean::Not(ref v) => {
                LinearCombination::<E>::zero() + (coeff, one) - (coeff, v.get_variable())
            }
        }
@@ -442,17 +443,17 @@ impl Boolean {
    /// Return a negated interpretation of this boolean.
    pub fn not(&self) -> Self {
-        match self {
+        match *self {
-            &Boolean::Constant(c) => Boolean::Constant(!c),
+            Boolean::Constant(c) => Boolean::Constant(!c),
-            &Boolean::Is(ref v) => Boolean::Not(v.clone()),
+            Boolean::Is(ref v) => Boolean::Not(v.clone()),
-            &Boolean::Not(ref v) => Boolean::Is(v.clone()),
+            Boolean::Not(ref v) => Boolean::Is(v.clone()),
        }
    }
    /// Perform XOR over two boolean operands
    pub fn xor<'a, E, CS>(cs: CS, a: &'a Self, b: &'a Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        match (a, b) {
@@ -474,7 +475,7 @@ impl Boolean {
    /// Perform AND over two boolean operands
    pub fn and<'a, E, CS>(cs: CS, a: &'a Self, b: &'a Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        match (a, b) {
@@ -508,7 +509,7 @@ impl Boolean {
        c: &'a Self,
    ) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let ch_value = match (a.get_value(), b.get_value(), c.get_value()) {
@@ -615,7 +616,7 @@ impl Boolean {
        c: &'a Self,
    ) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let maj_value = match (a.get_value(), b.get_value(), c.get_value()) {
@@ -1740,4 +1741,72 @@ mod test {
            }
        }
    }
    #[test]
    fn test_alloc_conditionally() {
        {
            let mut cs = TestConstraintSystem::<Bls12>::new();
            let b = AllocatedBit::alloc(&mut cs, Some(false)).unwrap();
            let value = None;
            // if value is none, fail with SynthesisError
            let is_err = AllocatedBit::alloc_conditionally(
                cs.namespace(|| "alloc_conditionally"),
                value,
                &b,
            )
            .is_err();
            assert!(is_err);
        }
        {
            // since value is true, b must be false, so it should succeed
            let mut cs = TestConstraintSystem::<Bls12>::new();
            let value = Some(true);
            let b = AllocatedBit::alloc(&mut cs, Some(false)).unwrap();
            let allocated_value = AllocatedBit::alloc_conditionally(
                cs.namespace(|| "alloc_conditionally"),
                value,
                &b,
            )
            .unwrap();
            assert_eq!(allocated_value.get_value().unwrap(), true);
            assert!(cs.is_satisfied());
        }
        {
            // since value is true, b must be false, so it should fail
            let mut cs = TestConstraintSystem::<Bls12>::new();
            let value = Some(true);
            let b = AllocatedBit::alloc(&mut cs, Some(true)).unwrap();
            AllocatedBit::alloc_conditionally(cs.namespace(|| "alloc_conditionally"), value, &b)
                .unwrap();
            assert!(!cs.is_satisfied());
        }
        {
            // since value is false, we don't care about the value of the bit
            let value = Some(false);
            //check with false bit
            let mut cs = TestConstraintSystem::<Bls12>::new();
            let b1 = AllocatedBit::alloc(&mut cs, Some(false)).unwrap();
            AllocatedBit::alloc_conditionally(cs.namespace(|| "alloc_conditionally"), value, &b1)
                .unwrap();
            assert!(cs.is_satisfied());
            //check with true bit
            let mut cs = TestConstraintSystem::<Bls12>::new();
            let b2 = AllocatedBit::alloc(&mut cs, Some(true)).unwrap();
            AllocatedBit::alloc_conditionally(cs.namespace(|| "alloc_conditionally"), value, &b2)
                .unwrap();
            assert!(cs.is_satisfied());
        }
    }
 }
--- a/bellman/src/gadgets/lookup.rs
+++ b/bellman/src/gadgets/lookup.rs
@@ -1,5 +1,6 @@
-use ff::Field;
+//! Window table lookup gadgets.
-use pairing::Engine;
+
 use ff::{Field, ScalarEngine};
 use super::boolean::Boolean;
 use super::num::{AllocatedNum, Num};
@@ -7,7 +8,7 @@ use super::*;
 use crate::ConstraintSystem;
 // Synthesize the constants for each base pattern.
-fn synth<'a, E: Engine, I>(window_size: usize, constants: I, assignment: &mut [E::Fr])
+fn synth<'a, E: ScalarEngine, I>(window_size: usize, constants: I, assignment: &mut [E::Fr])
 where
    I: IntoIterator<Item = &'a E::Fr>,
 {
@@ -28,7 +29,7 @@ where
 /// Performs a 3-bit window table lookup. `bits` is in
 /// little-endian order.
-pub fn lookup3_xy<E: Engine, CS>(
+pub fn lookup3_xy<E: ScalarEngine, CS>(
    mut cs: CS,
    bits: &[Boolean],
    coords: &[(E::Fr, E::Fr)],
@@ -118,7 +119,7 @@ where
 /// Performs a 3-bit window table lookup, where
 /// one of the bits is a sign bit.
-pub fn lookup3_xy_with_conditional_negation<E: Engine, CS>(
+pub fn lookup3_xy_with_conditional_negation<E: ScalarEngine, CS>(
    mut cs: CS,
    bits: &[Boolean],
    coords: &[(E::Fr, E::Fr)],
--- a/bellman/src/gadgets/multieq.rs
+++ b/bellman/src/gadgets/multieq.rs
@@ -1,9 +1,8 @@
-use ff::{Field, PrimeField};
+use ff::{Field, PrimeField, ScalarEngine};
 use pairing::Engine;
 use crate::{ConstraintSystem, LinearCombination, SynthesisError, Variable};
-pub struct MultiEq<E: Engine, CS: ConstraintSystem<E>> {
+pub struct MultiEq<E: ScalarEngine, CS: ConstraintSystem<E>> {
    cs: CS,
    ops: usize,
    bits_used: usize,
@@ -11,10 +10,10 @@ pub struct MultiEq<E: Engine, CS: ConstraintSystem<E>> {
    rhs: LinearCombination<E>,
 }
-impl<E: Engine, CS: ConstraintSystem<E>> MultiEq<E, CS> {
+impl<E: ScalarEngine, CS: ConstraintSystem<E>> MultiEq<E, CS> {
    pub fn new(cs: CS) -> Self {
        MultiEq {
-            cs: cs,
+            cs,
            ops: 0,
            bits_used: 0,
            lhs: LinearCombination::zero(),
@@ -58,7 +57,7 @@ impl<E: Engine, CS: ConstraintSystem<E>> MultiEq<E, CS> {
    }
 }
-impl<E: Engine, CS: ConstraintSystem<E>> Drop for MultiEq<E, CS> {
+impl<E: ScalarEngine, CS: ConstraintSystem<E>> Drop for MultiEq<E, CS> {
    fn drop(&mut self) {
        if self.bits_used > 0 {
            self.accumulate();
@@ -66,7 +65,7 @@ impl<E: Engine, CS: ConstraintSystem<E>> Drop for MultiEq<E, CS> {
    }
 }
-impl<E: Engine, CS: ConstraintSystem<E>> ConstraintSystem<E> for MultiEq<E, CS> {
+impl<E: ScalarEngine, CS: ConstraintSystem<E>> ConstraintSystem<E> for MultiEq<E, CS> {
    type Root = Self;
    fn one() -> Variable {
--- a/bellman/src/gadgets/multipack.rs
+++ b/bellman/src/gadgets/multipack.rs
@@ -1,15 +1,16 @@
 //! Helpers for packing vectors of bits into scalar field elements.
 use super::boolean::Boolean;
 use super::num::Num;
 use super::Assignment;
 use crate::{ConstraintSystem, SynthesisError};
-use ff::{Field, PrimeField};
+use ff::{Field, PrimeField, ScalarEngine};
 use pairing::Engine;
 /// Takes a sequence of booleans and exposes them as compact
 /// public inputs
 pub fn pack_into_inputs<E, CS>(mut cs: CS, bits: &[Boolean]) -> Result<(), SynthesisError>
 where
-    E: Engine,
+    E: ScalarEngine,
    CS: ConstraintSystem<E>,
 {
    for (i, bits) in bits.chunks(E::Fr::CAPACITY as usize).enumerate() {
@@ -49,7 +50,7 @@ pub fn bytes_to_bits_le(bytes: &[u8]) -> Vec<bool> {
        .collect()
 }
-pub fn compute_multipacking<E: Engine>(bits: &[bool]) -> Vec<E::Fr> {
+pub fn compute_multipacking<E: ScalarEngine>(bits: &[bool]) -> Vec<E::Fr> {
    let mut result = vec![];
    for bits in bits.chunks(E::Fr::CAPACITY as usize) {
--- a/bellman/src/gadgets/num.rs
+++ b/bellman/src/gadgets/num.rs
@@ -1,5 +1,6 @@
-use ff::{BitIterator, Field, PrimeField, PrimeFieldRepr};
+//! Gadgets representing numbers in the scalar field of the underlying curve.
-use pairing::Engine;
+
 use ff::{BitIterator, Field, PrimeField, PrimeFieldRepr, ScalarEngine};
 use crate::{ConstraintSystem, LinearCombination, SynthesisError, Variable};
@@ -7,12 +8,12 @@ use super::Assignment;
 use super::boolean::{self, AllocatedBit, Boolean};
-pub struct AllocatedNum<E: Engine> {
+pub struct AllocatedNum<E: ScalarEngine> {
    value: Option<E::Fr>,
    variable: Variable,
 }
-impl<E: Engine> Clone for AllocatedNum<E> {
+impl<E: ScalarEngine> Clone for AllocatedNum<E> {
    fn clone(&self) -> Self {
        AllocatedNum {
            value: self.value,
@@ -21,7 +22,7 @@ impl<E: Engine> Clone for AllocatedNum<E> {
    }
 }
-impl<E: Engine> AllocatedNum<E> {
+impl<E: ScalarEngine> AllocatedNum<E> {
    pub fn alloc<CS, F>(mut cs: CS, value: F) -> Result<Self, SynthesisError>
    where
        CS: ConstraintSystem<E>,
@@ -66,7 +67,7 @@ impl<E: Engine> AllocatedNum<E> {
    /// order, requiring that the representation
    /// strictly exists "in the field" (i.e., a
    /// congruency is not allowed.)
-    pub fn into_bits_le_strict<CS>(&self, mut cs: CS) -> Result<Vec<Boolean>, SynthesisError>
+    pub fn to_bits_le_strict<CS>(&self, mut cs: CS) -> Result<Vec<Boolean>, SynthesisError>
    where
        CS: ConstraintSystem<E>,
    {
@@ -75,10 +76,10 @@ impl<E: Engine> AllocatedNum<E> {
            v: &[AllocatedBit],
        ) -> Result<AllocatedBit, SynthesisError>
        where
-            E: Engine,
+            E: ScalarEngine,
            CS: ConstraintSystem<E>,
        {
-            assert!(v.len() > 0);
+            assert!(!v.is_empty());
            // Let's keep this simple for now and just AND them all
            // manually
@@ -132,7 +133,7 @@ impl<E: Engine> AllocatedNum<E> {
                current_run.push(a_bit.clone());
                result.push(a_bit);
            } else {
-                if current_run.len() > 0 {
+                if !current_run.is_empty() {
                    // This is the start of a run of zeros, but we need
                    // to k-ary AND against `last_run` first.
@@ -183,13 +184,13 @@ impl<E: Engine> AllocatedNum<E> {
        cs.enforce(|| "unpacking constraint", |lc| lc, |lc| lc, |_| lc);
        // Convert into booleans, and reverse for little-endian bit order
-        Ok(result.into_iter().map(|b| Boolean::from(b)).rev().collect())
+        Ok(result.into_iter().map(Boolean::from).rev().collect())
    }
    /// Convert the allocated number into its little-endian representation.
    /// Note that this does not strongly enforce that the commitment is
    /// "in the field."
-    pub fn into_bits_le<CS>(&self, mut cs: CS) -> Result<Vec<Boolean>, SynthesisError>
+    pub fn to_bits_le<CS>(&self, mut cs: CS) -> Result<Vec<Boolean>, SynthesisError>
    where
        CS: ConstraintSystem<E>,
    {
@@ -208,7 +209,7 @@ impl<E: Engine> AllocatedNum<E> {
        cs.enforce(|| "unpacking constraint", |lc| lc, |lc| lc, |_| lc);
-        Ok(bits.into_iter().map(|b| Boolean::from(b)).collect())
+        Ok(bits.into_iter().map(Boolean::from).collect())
    }
    pub fn mul<CS>(&self, mut cs: CS, other: &Self) -> Result<Self, SynthesisError>
@@ -238,7 +239,7 @@ impl<E: Engine> AllocatedNum<E> {
        );
        Ok(AllocatedNum {
-            value: value,
+            value,
            variable: var,
        })
    }
@@ -270,7 +271,7 @@ impl<E: Engine> AllocatedNum<E> {
        );
        Ok(AllocatedNum {
-            value: value,
+            value,
            variable: var,
        })
    }
@@ -359,12 +360,12 @@ impl<E: Engine> AllocatedNum<E> {
    }
 }
-pub struct Num<E: Engine> {
+pub struct Num<E: ScalarEngine> {
    value: Option<E::Fr>,
    lc: LinearCombination<E>,
 }
-impl<E: Engine> From<AllocatedNum<E>> for Num<E> {
+impl<E: ScalarEngine> From<AllocatedNum<E>> for Num<E> {
    fn from(num: AllocatedNum<E>) -> Num<E> {
        Num {
            value: num.value,
@@ -373,7 +374,7 @@ impl<E: Engine> From<AllocatedNum<E>> for Num<E> {
    }
 }
-impl<E: Engine> Num<E> {
+impl<E: ScalarEngine> Num<E> {
    pub fn zero() -> Self {
        Num {
            value: Some(E::Fr::zero()),
@@ -522,7 +523,7 @@ mod test {
        let mut cs = TestConstraintSystem::<Bls12>::new();
        let n = AllocatedNum::alloc(&mut cs, || Ok(negone)).unwrap();
-        n.into_bits_le_strict(&mut cs).unwrap();
+        n.to_bits_le_strict(&mut cs).unwrap();
        assert!(cs.is_satisfied());
@@ -550,9 +551,9 @@ mod test {
            let n = AllocatedNum::alloc(&mut cs, || Ok(r)).unwrap();
            let bits = if i % 2 == 0 {
-                n.into_bits_le(&mut cs).unwrap()
+                n.to_bits_le(&mut cs).unwrap()
            } else {
-                n.into_bits_le_strict(&mut cs).unwrap()
+                n.to_bits_le_strict(&mut cs).unwrap()
            };
            assert!(cs.is_satisfied());
--- a/bellman/src/gadgets/sha256.rs
+++ b/bellman/src/gadgets/sha256.rs
@@ -1,9 +1,15 @@
 //! Circuits for the [SHA-256] hash function and its internal compression
 //! function.
 //!
 //! [SHA-256]: https://tools.ietf.org/html/rfc6234
 use super::boolean::Boolean;
 use super::multieq::MultiEq;
 use super::uint32::UInt32;
 use crate::{ConstraintSystem, SynthesisError};
-use pairing::Engine;
+use ff::ScalarEngine;
 #[allow(clippy::unreadable_literal)]
 const ROUND_CONSTANTS: [u32; 64] = [
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
@@ -15,6 +21,7 @@ const ROUND_CONSTANTS: [u32; 64] = [
    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
 ];
 #[allow(clippy::unreadable_literal)]
 const IV: [u32; 8] = [
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
 ];
@@ -24,7 +31,7 @@ pub fn sha256_block_no_padding<E, CS>(
    input: &[Boolean],
 ) -> Result<Vec<Boolean>, SynthesisError>
 where
-    E: Engine,
+    E: ScalarEngine,
    CS: ConstraintSystem<E>,
 {
    assert_eq!(input.len(), 512);
@@ -39,7 +46,7 @@ where
 pub fn sha256<E, CS>(mut cs: CS, input: &[Boolean]) -> Result<Vec<Boolean>, SynthesisError>
 where
-    E: Engine,
+    E: ScalarEngine,
    CS: ConstraintSystem<E>,
 {
    assert!(input.len() % 8 == 0);
@@ -76,7 +83,7 @@ fn sha256_compression_function<E, CS>(
    current_hash_value: &[UInt32],
 ) -> Result<Vec<UInt32>, SynthesisError>
 where
-    E: Engine,
+    E: ScalarEngine,
    CS: ConstraintSystem<E>,
 {
    assert_eq!(input.len(), 512);
@@ -123,14 +130,14 @@ where
    impl Maybe {
        fn compute<E, CS, M>(self, cs: M, others: &[UInt32]) -> Result<UInt32, SynthesisError>
        where
-            E: Engine,
+            E: ScalarEngine,
            CS: ConstraintSystem<E>,
            M: ConstraintSystem<E, Root = MultiEq<E, CS>>,
        {
            Ok(match self {
                Maybe::Concrete(ref v) => return Ok(v.clone()),
                Maybe::Deferred(mut v) => {
-                    v.extend(others.into_iter().cloned());
+                    v.extend(others.iter().cloned());
                    UInt32::addmany(cs, &v)?
                }
            })
@@ -266,6 +273,7 @@ mod test {
    use super::*;
    use crate::gadgets::boolean::AllocatedBit;
    use crate::gadgets::test::TestConstraintSystem;
    use hex_literal::hex;
    use pairing::bls12_381::Bls12;
    use rand_core::{RngCore, SeedableRng};
    use rand_xorshift::XorShiftRng;
@@ -286,7 +294,7 @@ mod test {
        let expected = hex!("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
        let mut out = out_bits.into_iter();
-        for b in expected.into_iter() {
+        for b in expected.iter() {
            for i in (0..8).rev() {
                let c = out.next().unwrap().get_value().unwrap();
--- a/bellman/src/gadgets/test/mod.rs
+++ b/bellman/src/gadgets/test/mod.rs
@@ -1,5 +1,6 @@
-use ff::{Field, PrimeField, PrimeFieldRepr};
+//! Helpers for testing circuit implementations.
-use pairing::Engine;
+
 use ff::{Field, PrimeField, PrimeFieldRepr, ScalarEngine};
 use crate::{ConstraintSystem, Index, LinearCombination, SynthesisError, Variable};
@@ -20,7 +21,7 @@ enum NamedObject {
 }
 /// Constraint system for testing purposes.
-pub struct TestConstraintSystem<E: Engine> {
+pub struct TestConstraintSystem<E: ScalarEngine> {
    named_objects: HashMap<String, NamedObject>,
    current_namespace: Vec<String>,
    constraints: Vec<(
@@ -62,11 +63,11 @@ impl Ord for OrderedVariable {
    }
 }
-fn proc_lc<E: Engine>(terms: &[(Variable, E::Fr)]) -> BTreeMap<OrderedVariable, E::Fr> {
+fn proc_lc<E: ScalarEngine>(terms: &[(Variable, E::Fr)]) -> BTreeMap<OrderedVariable, E::Fr> {
    let mut map = BTreeMap::new();
    for &(var, coeff) in terms {
        map.entry(OrderedVariable(var))
-            .or_insert(E::Fr::zero())
+            .or_insert_with(E::Fr::zero)
            .add_assign(&coeff);
    }
@@ -85,7 +86,7 @@ fn proc_lc<E: Engine>(terms: &[(Variable, E::Fr)]) -> BTreeMap<OrderedVariable,
    map
 }
-fn hash_lc<E: Engine>(terms: &[(Variable, E::Fr)], h: &mut Blake2sState) {
+fn hash_lc<E: ScalarEngine>(terms: &[(Variable, E::Fr)], h: &mut Blake2sState) {
    let map = proc_lc::<E>(terms);
    let mut buf = [0u8; 9 + 32];
@@ -110,7 +111,7 @@ fn hash_lc<E: Engine>(terms: &[(Variable, E::Fr)], h: &mut Blake2sState) {
    }
 }
-fn eval_lc<E: Engine>(
+fn eval_lc<E: ScalarEngine>(
    terms: &[(Variable, E::Fr)],
    inputs: &[(E::Fr, String)],
    aux: &[(E::Fr, String)],
@@ -130,7 +131,7 @@ fn eval_lc<E: Engine>(
    acc
 }
-impl<E: Engine> TestConstraintSystem<E> {
+impl<E: ScalarEngine> TestConstraintSystem<E> {
    pub fn new() -> TestConstraintSystem<E> {
        let mut map = HashMap::new();
        map.insert(
@@ -157,7 +158,7 @@ impl<E: Engine> TestConstraintSystem<E> {
        };
        let powers_of_two = (0..E::Fr::NUM_BITS)
-            .map(|i| E::Fr::from_str("2").unwrap().pow(&[i as u64]))
+            .map(|i| E::Fr::from_str("2").unwrap().pow(&[u64::from(i)]))
            .collect::<Vec<_>>();
        let pp = |s: &mut String, lc: &LinearCombination<E>| {
@@ -286,7 +287,7 @@ impl<E: Engine> TestConstraintSystem<E> {
            }
        }
-        return true;
+        true
    }
    pub fn num_inputs(&self) -> usize {
@@ -344,7 +345,7 @@ fn compute_path(ns: &[String], this: String) -> String {
    name
 }
-impl<E: Engine> ConstraintSystem<E> for TestConstraintSystem<E> {
+impl<E: ScalarEngine> ConstraintSystem<E> for TestConstraintSystem<E> {
    type Root = Self;
    fn alloc<F, A, AR>(&mut self, annotation: A, f: F) -> Result<Variable, SynthesisError>
--- a/bellman/src/gadgets/uint32.rs
+++ b/bellman/src/gadgets/uint32.rs
@@ -1,5 +1,9 @@
-use ff::{Field, PrimeField};
+//! Circuit representation of a [`u32`], with helpers for the [`sha256`]
-use pairing::Engine;
+//! gadgets.
 //!
 //! [`sha256`]: crate::gadgets::sha256
 use ff::{Field, PrimeField, ScalarEngine};
 use crate::{ConstraintSystem, LinearCombination, SynthesisError};
@@ -33,7 +37,7 @@ impl UInt32 {
        }
        UInt32 {
-            bits: bits,
+            bits,
            value: Some(value),
        }
    }
@@ -41,7 +45,7 @@ impl UInt32 {
    /// Allocate a `UInt32` in the constraint system
    pub fn alloc<E, CS>(mut cs: CS, value: Option<u32>) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let values = match value {
@@ -69,14 +73,13 @@ impl UInt32 {
            })
            .collect::<Result<Vec<_>, SynthesisError>>()?;
-        Ok(UInt32 {
+        Ok(UInt32 { bits, value })
            bits: bits,
            value: value,
        })
    }
-    pub fn into_bits_be(&self) -> Vec<Boolean> {
+    pub fn into_bits_be(self) -> Vec<Boolean> {
-        self.bits.iter().rev().cloned().collect()
+        let mut ret = self.bits;
        ret.reverse();
        ret
    }
    pub fn from_bits_be(bits: &[Boolean]) -> Self {
@@ -98,14 +101,14 @@ impl UInt32 {
        }
        UInt32 {
-            value: value,
+            value,
            bits: bits.iter().rev().cloned().collect(),
        }
    }
    /// Turns this `UInt32` into its little-endian byte order representation.
-    pub fn into_bits(&self) -> Vec<Boolean> {
+    pub fn into_bits(self) -> Vec<Boolean> {
-        self.bits.clone()
+        self.bits
    }
    /// Converts a little-endian byte order representation of bits into a
@@ -119,20 +122,20 @@ impl UInt32 {
        for b in new_bits.iter().rev() {
            value.as_mut().map(|v| *v <<= 1);
-            match b {
+            match *b {
-                &Boolean::Constant(b) => {
+                Boolean::Constant(b) => {
                    if b {
                        value.as_mut().map(|v| *v |= 1);
                    }
                }
-                &Boolean::Is(ref b) => match b.get_value() {
+                Boolean::Is(ref b) => match b.get_value() {
                    Some(true) => {
                        value.as_mut().map(|v| *v |= 1);
                    }
                    Some(false) => {}
                    None => value = None,
                },
-                &Boolean::Not(ref b) => match b.get_value() {
+                Boolean::Not(ref b) => match b.get_value() {
                    Some(false) => {
                        value.as_mut().map(|v| *v |= 1);
                    }
@@ -143,7 +146,7 @@ impl UInt32 {
        }
        UInt32 {
-            value: value,
+            value,
            bits: new_bits,
        }
    }
@@ -195,7 +198,7 @@ impl UInt32 {
        circuit_fn: U,
    ) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
        F: Fn(u32, u32, u32) -> u32,
        U: Fn(&mut CS, usize, &Boolean, &Boolean, &Boolean) -> Result<Boolean, SynthesisError>,
@@ -215,7 +218,7 @@ impl UInt32 {
            .collect::<Result<_, _>>()?;
        Ok(UInt32 {
-            bits: bits,
+            bits,
            value: new_value,
        })
    }
@@ -224,7 +227,7 @@ impl UInt32 {
    /// during SHA256.
    pub fn sha256_maj<E, CS>(cs: CS, a: &Self, b: &Self, c: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        Self::triop(
@@ -241,7 +244,7 @@ impl UInt32 {
    /// during SHA256.
    pub fn sha256_ch<E, CS>(cs: CS, a: &Self, b: &Self, c: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        Self::triop(
@@ -257,7 +260,7 @@ impl UInt32 {
    /// XOR this `UInt32` with another `UInt32`
    pub fn xor<E, CS>(&self, mut cs: CS, other: &Self) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
    {
        let new_value = match (self.value, other.value) {
@@ -274,7 +277,7 @@ impl UInt32 {
            .collect::<Result<_, _>>()?;
        Ok(UInt32 {
-            bits: bits,
+            bits,
            value: new_value,
        })
    }
@@ -282,7 +285,7 @@ impl UInt32 {
    /// Perform modular addition of several `UInt32` objects.
    pub fn addmany<E, CS, M>(mut cs: M, operands: &[Self]) -> Result<Self, SynthesisError>
    where
-        E: Engine,
+        E: ScalarEngine,
        CS: ConstraintSystem<E>,
        M: ConstraintSystem<E, Root = MultiEq<E, CS>>,
    {
@@ -294,7 +297,7 @@ impl UInt32 {
        // Compute the maximum value of the sum so we allocate enough bits for
        // the result
-        let mut max_value = (operands.len() as u64) * (u32::max_value() as u64);
+        let mut max_value = (operands.len() as u64) * (u64::from(u32::max_value()));
        // Keep track of the resulting value
        let mut result_value = Some(0u64);
@@ -310,7 +313,7 @@ impl UInt32 {
            // Accumulate the value
            match op.value {
                Some(val) => {
-                    result_value.as_mut().map(|v| *v += val as u64);
+                    result_value.as_mut().map(|v| *v += u64::from(val));
                }
                None => {
                    // If any of our operands have unknown value, we won't
@@ -401,15 +404,15 @@ mod test {
        ]);
        for _ in 0..1000 {
-            let mut v = (0..32)
+            let v = (0..32)
                .map(|_| Boolean::constant(rng.next_u32() % 2 != 0))
                .collect::<Vec<_>>();
            let b = UInt32::from_bits_be(&v);
            for (i, bit) in b.bits.iter().enumerate() {
-                match bit {
+                match *bit {
-                    &Boolean::Constant(bit) => {
+                    Boolean::Constant(bit) => {
                        assert!(bit == ((b.value.unwrap() >> i) & 1 == 1));
                    }
                    _ => unreachable!(),
@@ -436,15 +439,15 @@ mod test {
        ]);
        for _ in 0..1000 {
-            let mut v = (0..32)
+            let v = (0..32)
                .map(|_| Boolean::constant(rng.next_u32() % 2 != 0))
                .collect::<Vec<_>>();
            let b = UInt32::from_bits(&v);
            for (i, bit) in b.bits.iter().enumerate() {
-                match bit {
+                match *bit {
-                    &Boolean::Constant(bit) => {
+                    Boolean::Constant(bit) => {
                        assert!(bit == ((b.value.unwrap() >> i) & 1 == 1));
                    }
                    _ => unreachable!(),
@@ -491,14 +494,14 @@ mod test {
            assert!(r.value == Some(expected));
            for b in r.bits.iter() {
-                match b {
+                match *b {
-                    &Boolean::Is(ref b) => {
+                    Boolean::Is(ref b) => {
                        assert!(b.get_value().unwrap() == (expected & 1 == 1));
                    }
-                    &Boolean::Not(ref b) => {
+                    Boolean::Not(ref b) => {
                        assert!(!b.get_value().unwrap() == (expected & 1 == 1));
                    }
-                    &Boolean::Constant(b) => {
+                    Boolean::Constant(b) => {
                        assert!(b == (expected & 1 == 1));
                    }
                }
@@ -538,10 +541,10 @@ mod test {
            assert!(r.value == Some(expected));
            for b in r.bits.iter() {
-                match b {
+                match *b {
-                    &Boolean::Is(_) => panic!(),
+                    Boolean::Is(_) => panic!(),
-                    &Boolean::Not(_) => panic!(),
+                    Boolean::Not(_) => panic!(),
-                    &Boolean::Constant(b) => {
+                    Boolean::Constant(b) => {
                        assert!(b == (expected & 1 == 1));
                    }
                }
@@ -576,8 +579,7 @@ mod test {
            let r = a_bit.xor(cs.namespace(|| "xor"), &b_bit).unwrap();
            let r = {
                let mut cs = MultiEq::new(&mut cs);
-                let r = UInt32::addmany(cs.namespace(|| "addition"), &[r, c_bit, d_bit]).unwrap();
+                UInt32::addmany(cs.namespace(|| "addition"), &[r, c_bit, d_bit]).unwrap()
                r
            };
            assert!(cs.is_satisfied());
@@ -585,14 +587,14 @@ mod test {
            assert!(r.value == Some(expected));
            for b in r.bits.iter() {
-                match b {
+                match *b {
-                    &Boolean::Is(ref b) => {
+                    Boolean::Is(ref b) => {
                        assert!(b.get_value().unwrap() == (expected & 1 == 1));
                    }
-                    &Boolean::Not(ref b) => {
+                    Boolean::Not(ref b) => {
                        assert!(!b.get_value().unwrap() == (expected & 1 == 1));
                    }
-                    &Boolean::Constant(_) => unreachable!(),
+                    Boolean::Constant(_) => unreachable!(),
                }
                expected >>= 1;
@@ -628,8 +630,8 @@ mod test {
            let mut tmp = num;
            for b in &b.bits {
-                match b {
+                match *b {
-                    &Boolean::Constant(b) => {
+                    Boolean::Constant(b) => {
                        assert_eq!(b, tmp & 1 == 1);
                    }
                    _ => unreachable!(),
--- a/bellman/src/groth16/generator.rs
+++ b/bellman/src/groth16/generator.rs
@@ -8,11 +8,11 @@ use pairing::Engine;
 use super::{Parameters, VerifyingKey};
-use {Circuit, ConstraintSystem, Index, LinearCombination, SynthesisError, Variable};
+use crate::{Circuit, ConstraintSystem, Index, LinearCombination, SynthesisError, Variable};
-use domain::{EvaluationDomain, Scalar};
+use crate::domain::{EvaluationDomain, Scalar};
-use multicore::Worker;
+use crate::multicore::Worker;
 /// Generates a random common reference string for
 /// a circuit.
@@ -227,7 +227,7 @@ where
            let powers_of_tau = powers_of_tau.as_mut();
            worker.scope(powers_of_tau.len(), |scope, chunk| {
                for (i, powers_of_tau) in powers_of_tau.chunks_mut(chunk).enumerate() {
-                    scope.spawn(move || {
+                    scope.spawn(move |_scope| {
                        let mut current_tau_power = tau.pow(&[(i * chunk) as u64]);
                        for p in powers_of_tau {
@@ -251,7 +251,7 @@ where
            {
                let mut g1_wnaf = g1_wnaf.shared();
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    // Set values of the H query to g1^{(tau^i * t(tau)) / delta}
                    for (h, p) in h.iter_mut().zip(p.iter()) {
                        // Compute final exponent
@@ -330,7 +330,7 @@ where
                let mut g1_wnaf = g1_wnaf.shared();
                let mut g2_wnaf = g2_wnaf.shared();
-                scope.spawn(move || {
+                scope.spawn(move |_scope| {
                    for ((((((a, b_g1), b_g2), ext), at), bt), ct) in a
                        .iter_mut()
                        .zip(b_g1.iter_mut())
@@ -451,7 +451,7 @@ where
    };
    Ok(Parameters {
-        vk: vk,
+        vk,
        h: Arc::new(h.into_iter().map(|e| e.into_affine()).collect()),
        l: Arc::new(l.into_iter().map(|e| e.into_affine()).collect()),
--- a/bellman/src/groth16/mod.rs
+++ b/bellman/src/groth16/mod.rs
@@ -1,10 +1,14 @@
 //! The [Groth16] proving system.
 //!
 //! [Groth16]: https://eprint.iacr.org/2016/260
 use group::{CurveAffine, EncodedPoint};
 use pairing::{Engine, PairingCurveAffine};
-use SynthesisError;
+use crate::SynthesisError;
 use crate::multiexp::SourceBuilder;
 use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
 use multiexp::SourceBuilder;
 use std::io::{self, Read, Write};
 use std::sync::Arc;
@@ -90,7 +94,7 @@ impl<E: Engine> Proof<E> {
                }
            })?;
-        Ok(Proof { a: a, b: b, c: c })
+        Ok(Proof { a, b, c })
    }
 }
@@ -208,13 +212,13 @@ impl<E: Engine> VerifyingKey<E> {
        }
        Ok(VerifyingKey {
-            alpha_g1: alpha_g1,
+            alpha_g1,
-            beta_g1: beta_g1,
+            beta_g1,
-            beta_g2: beta_g2,
+            beta_g2,
-            gamma_g2: gamma_g2,
+            gamma_g2,
-            delta_g1: delta_g1,
+            delta_g1,
-            delta_g2: delta_g2,
+            delta_g2,
-            ic: ic,
+            ic,
        })
    }
 }
@@ -376,7 +380,7 @@ impl<E: Engine> Parameters<E> {
        }
        Ok(Parameters {
-            vk: vk,
+            vk,
            h: Arc::new(h),
            l: Arc::new(l),
            a: Arc::new(a),
@@ -465,7 +469,7 @@ impl<'a, E: Engine> ParameterSource<E> for &'a Parameters<E> {
 #[cfg(test)]
 mod test_with_bls12_381 {
    use super::*;
-    use {Circuit, ConstraintSystem, SynthesisError};
+    use crate::{Circuit, ConstraintSystem, SynthesisError};
    use ff::Field;
    use pairing::bls12_381::{Bls12, Fr};
--- a/bellman/src/groth16/prover.rs
+++ b/bellman/src/groth16/prover.rs
@@ -10,13 +10,13 @@ use pairing::Engine;
 use super::{ParameterSource, Proof};
-use {Circuit, ConstraintSystem, Index, LinearCombination, SynthesisError, Variable};
+use crate::{Circuit, ConstraintSystem, Index, LinearCombination, SynthesisError, Variable};
-use domain::{EvaluationDomain, Scalar};
+use crate::domain::{EvaluationDomain, Scalar};
-use multiexp::{multiexp, DensityTracker, FullDensity};
+use crate::multiexp::{multiexp, DensityTracker, FullDensity};
-use multicore::Worker;
+use crate::multicore::Worker;
 fn eval<E: Engine>(
    lc: &LinearCombination<E>,
--- a/bellman/src/groth16/tests/dummy_engine.rs
+++ b/bellman/src/groth16/tests/dummy_engine.rs
@@ -16,13 +16,13 @@ const MODULUS_R: Wrapping<u32> = Wrapping(64513);
 pub struct Fr(Wrapping<u32>);
 impl fmt::Display for Fr {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
        write!(f, "{}", (self.0).0)
    }
 }
 impl Field for Fr {
-    fn random<R: RngCore>(rng: &mut R) -> Self {
+    fn random<R: RngCore + ?std::marker::Sized>(rng: &mut R) -> Self {
        Fr(Wrapping(rng.next_u32()) % MODULUS_R)
    }
@@ -149,7 +149,7 @@ impl PartialOrd for FrRepr {
 }
 impl fmt::Display for FrRepr {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
        write!(f, "{}", (self.0)[0])
    }
 }
--- a/bellman/src/groth16/tests/mod.rs
+++ b/bellman/src/groth16/tests/mod.rs
@@ -6,7 +6,7 @@ use self::dummy_engine::*;
 use std::marker::PhantomData;
-use {Circuit, ConstraintSystem, SynthesisError};
+use crate::{Circuit, ConstraintSystem, SynthesisError};
 use super::{create_proof, generate_parameters, prepare_verifying_key, verify_proof};
--- a/bellman/src/groth16/verifier.rs
+++ b/bellman/src/groth16/verifier.rs
@@ -4,7 +4,7 @@ use pairing::{Engine, PairingCurveAffine};
 use super::{PreparedVerifyingKey, Proof, VerifyingKey};
-use SynthesisError;
+use crate::SynthesisError;
 pub fn prepare_verifying_key<E: Engine>(vk: &VerifyingKey<E>) -> PreparedVerifyingKey<E> {
    let mut gamma = vk.gamma_g2;
@@ -49,7 +49,7 @@ pub fn verify_proof<'a, E: Engine>(
            (&acc.into_affine().prepare(), &pvk.neg_gamma_g2),
            (&proof.c.prepare(), &pvk.neg_delta_g2),
        ]
-        .into_iter(),
+        .iter(),
    ))
    .unwrap()
        == pvk.alpha_g1_beta_g2)
--- a/bellman/src/lib.rs
+++ b/bellman/src/lib.rs
@@ -1,33 +1,139 @@
-extern crate ff;
+//! `bellman` is a crate for building zk-SNARK circuits. It provides circuit
-extern crate group;
+//! traits and and primitive structures, as well as basic gadget implementations
-#[cfg(feature = "pairing")]
+//! such as booleans and number abstractions.
-extern crate pairing;
+//!
-extern crate rand_core;
+//! # Example circuit
 //!
 //! Say we want to write a circuit that proves we know the preimage to some hash
 //! computed using SHA-256d (calling SHA-256 twice). The preimage must have a
 //! fixed length known in advance (because the circuit parameters will depend on
 //! it), but can otherwise have any value. We take the following strategy:
 //!
 //! - Witness each bit of the preimage.
 //! - Compute `hash = SHA-256d(preimage)` inside the circuit.
 //! - Expose `hash` as a public input using multiscalar packing.
 //!
 //! ```
 //! use bellman::{
 //!     gadgets::{
 //!         boolean::{AllocatedBit, Boolean},
 //!         multipack,
 //!         sha256::sha256,
 //!     },
 //!     groth16, Circuit, ConstraintSystem, SynthesisError,
 //! };
 //! use pairing::{bls12_381::Bls12, Engine};
 //! use rand::rngs::OsRng;
 //! use sha2::{Digest, Sha256};
 //!
 //! /// Our own SHA-256d gadget. Input and output are in little-endian bit order.
 //! fn sha256d<E: Engine, CS: ConstraintSystem<E>>(
 //!     mut cs: CS,
 //!     data: &[Boolean],
 //! ) -> Result<Vec<Boolean>, SynthesisError> {
 //!     // Flip endianness of each input byte
 //!     let input: Vec<_> = data
 //!         .chunks(8)
 //!         .map(|c| c.iter().rev())
 //!         .flatten()
 //!         .cloned()
 //!         .collect();
 //!
 //!     let mid = sha256(cs.namespace(|| "SHA-256(input)"), &input)?;
 //!     let res = sha256(cs.namespace(|| "SHA-256(mid)"), &mid)?;
 //!
 //!     // Flip endianness of each output byte
 //!     Ok(res
 //!         .chunks(8)
 //!         .map(|c| c.iter().rev())
 //!         .flatten()
 //!         .cloned()
 //!         .collect())
 //! }
 //!
 //! struct MyCircuit {
 //!     /// The input to SHA-256d we are proving that we know. Set to `None` when we
 //!     /// are verifying a proof (and do not have the witness data).
 //!     preimage: Option<[u8; 80]>,
 //! }
 //!
 //! impl<E: Engine> Circuit<E> for MyCircuit {
 //!     fn synthesize<CS: ConstraintSystem<E>>(self, cs: &mut CS) -> Result<(), SynthesisError> {
 //!         // Compute the values for the bits of the preimage. If we are verifying a proof,
 //!         // we still need to create the same constraints, so we return an equivalent-size
 //!         // Vec of None (indicating that the value of each bit is unknown).
 //!         let bit_values = if let Some(preimage) = self.preimage {
 //!             preimage
 //!                 .into_iter()
 //!                 .map(|byte| (0..8).map(move |i| (byte >> i) & 1u8 == 1u8))
 //!                 .flatten()
 //!                 .map(|b| Some(b))
 //!                 .collect()
 //!         } else {
 //!             vec![None; 80 * 8]
 //!         };
 //!         assert_eq!(bit_values.len(), 80 * 8);
 //!
 //!         // Witness the bits of the preimage.
 //!         let preimage_bits = bit_values
 //!             .into_iter()
 //!             .enumerate()
 //!             // Allocate each bit.
 //!             .map(|(i, b)| {
 //!                 AllocatedBit::alloc(cs.namespace(|| format!("preimage bit {}", i)), b)
 //!             })
 //!             // Convert the AllocatedBits into Booleans (required for the sha256 gadget).
 //!             .map(|b| b.map(Boolean::from))
 //!             .collect::<Result<Vec<_>, _>>()?;
 //!
 //!         // Compute hash = SHA-256d(preimage).
 //!         let hash = sha256d(cs.namespace(|| "SHA-256d(preimage)"), &preimage_bits)?;
 //!
 //!         // Expose the vector of 32 boolean variables as compact public inputs.
 //!         multipack::pack_into_inputs(cs.namespace(|| "pack hash"), &hash)
 //!     }
 //! }
 //!
 //! // Create parameters for our circuit. In a production deployment these would
 //! // be generated securely using a multiparty computation.
 //! let params = {
 //!     let c = MyCircuit { preimage: None };
 //!     groth16::generate_random_parameters::<Bls12, _, _>(c, &mut OsRng).unwrap()
 //! };
 //!
 //! // Prepare the verification key (for proof verification).
 //! let pvk = groth16::prepare_verifying_key(&params.vk);
 //!
 //! // Pick a preimage and compute its hash.
 //! let preimage = [42; 80];
 //! let hash = Sha256::digest(&Sha256::digest(&preimage));
 //!
 //! // Create an instance of our circuit (with the preimage as a witness).
 //! let c = MyCircuit {
 //!     preimage: Some(preimage),
 //! };
 //!
 //! // Create a Groth16 proof with our parameters.
 //! let proof = groth16::create_random_proof(c, &params, &mut OsRng).unwrap();
 //!
 //! // Pack the hash as inputs for proof verification.
 //! let hash_bits = multipack::bytes_to_bits_le(&hash);
 //! let inputs = multipack::compute_multipacking::<Bls12>(&hash_bits);
 //!
 //! // Check the proof!
 //! assert!(groth16::verify_proof(&pvk, &proof, &inputs).unwrap());
 //! ```
 //!
 //! # Roadmap
 //!
 //! `bellman` is being refactored into a generic proving library. Currently it
 //! is pairing-specific, and different types of proving systems need to be
 //! implemented as sub-modules. After the refactor, `bellman` will be generic
 //! using the [`ff`] and [`group`] crates, while specific proving systems will
 //! be separate crates that pull in the dependencies they require.
-extern crate bit_vec;
+// Catch documentation errors caused by code changes.
-extern crate blake2s_simd;
+#![deny(intra_doc_link_resolution_failure)]
 extern crate byteorder;
 extern crate futures;
 #[cfg(feature = "multicore")]
 extern crate crossbeam;
 #[cfg(feature = "multicore")]
 extern crate futures_cpupool;
 #[cfg(feature = "multicore")]
 extern crate num_cpus;
 #[cfg(test)]
 #[macro_use]
 extern crate hex_literal;
 #[cfg(test)]
 extern crate rand;
 #[cfg(test)]
 extern crate rand_xorshift;
 #[cfg(test)]
 extern crate sha2;
 pub mod domain;
 pub mod gadgets;
@@ -109,6 +215,7 @@ impl<E: ScalarEngine> Add<(E::Fr, Variable)> for LinearCombination<E> {
 impl<E: ScalarEngine> Sub<(E::Fr, Variable)> for LinearCombination<E> {
    type Output = LinearCombination<E>;
    #[allow(clippy::suspicious_arithmetic_impl)]
    fn sub(self, (mut coeff, var): (E::Fr, Variable)) -> LinearCombination<E> {
        coeff.negate();
@@ -230,8 +337,8 @@ impl Error for SynthesisError {
 }
 impl fmt::Display for SynthesisError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        if let &SynthesisError::IoError(ref e) = self {
+        if let SynthesisError::IoError(ref e) = *self {
            write!(f, "I/O error: ")?;
            e.fmt(f)
        } else {
@@ -296,7 +403,7 @@ pub trait ConstraintSystem<E: ScalarEngine>: Sized {
    fn get_root(&mut self) -> &mut Self::Root;
    /// Begin a namespace for this constraint system.
-    fn namespace<'a, NR, N>(&'a mut self, name_fn: N) -> Namespace<'a, E, Self::Root>
+    fn namespace<NR, N>(&mut self, name_fn: N) -> Namespace<'_, E, Self::Root>
    where
        NR: Into<String>,
        N: FnOnce() -> NR,
@@ -309,7 +416,7 @@ pub trait ConstraintSystem<E: ScalarEngine>: Sized {
 /// This is a "namespaced" constraint system which borrows a constraint system (pushing
 /// a namespace context) and, when dropped, pops out of the namespace context.
-pub struct Namespace<'a, E: ScalarEngine, CS: ConstraintSystem<E> + 'a>(&'a mut CS, PhantomData<E>);
+pub struct Namespace<'a, E: ScalarEngine, CS: ConstraintSystem<E>>(&'a mut CS, PhantomData<E>);
 impl<'cs, E: ScalarEngine, CS: ConstraintSystem<E>> ConstraintSystem<E> for Namespace<'cs, E, CS> {
    type Root = CS::Root;
--- a/bellman/src/multicore.rs
+++ b/bellman/src/multicore.rs
@@ -1,12 +1,13 @@
-//! This is an interface for dealing with the kinds of
+//! An interface for dealing with the kinds of parallel computations involved in
-//! parallel computations involved in bellman. It's
+//! `bellman`. It's currently just a thin wrapper around [`CpuPool`] and
-//! currently just a thin wrapper around CpuPool and
+//! [`crossbeam`] but may be extended in the future to allow for various
-//! crossbeam but may be extended in the future to
+//! parallelism strategies.
-//! allow for various parallelism strategies.
+//!
 //! [`CpuPool`]: futures_cpupool::CpuPool
 #[cfg(feature = "multicore")]
 mod implementation {
-    use crossbeam::{self, Scope};
+    use crossbeam::{self, thread::Scope};
    use futures::{Future, IntoFuture, Poll};
    use futures_cpupool::{CpuFuture, CpuPool};
    use num_cpus;
@@ -23,7 +24,7 @@ mod implementation {
        // CPUs configured.
        pub(crate) fn new_with_cpus(cpus: usize) -> Worker {
            Worker {
-                cpus: cpus,
+                cpus,
                pool: CpuPool::new(cpus),
            }
        }
@@ -59,7 +60,9 @@ mod implementation {
                elements / self.cpus
            };
            // TODO: Handle case where threads fail
            crossbeam::scope(|scope| f(scope, chunk_size))
                .expect("Threads aren't allowed to fail yet")
        }
    }
@@ -152,8 +155,8 @@ mod implementation {
    pub struct DummyScope;
    impl DummyScope {
-        pub fn spawn<F: FnOnce()>(&self, f: F) {
+        pub fn spawn<F: FnOnce(&DummyScope)>(&self, f: F) {
-            f();
+            f(self);
        }
    }
 }
--- a/bellman/src/multiexp.rs
+++ b/bellman/src/multiexp.rs
@@ -153,7 +153,7 @@ fn multiexp_inner<Q, D, G, S>(
    mut skip: u32,
    c: u32,
    handle_trivial: bool,
-) -> Box<Future<Item = <G as CurveAffine>::Projective, Error = SynthesisError>>
+) -> Box<dyn Future<Item = <G as CurveAffine>::Projective, Error = SynthesisError>>
 where
    for<'a> &'a Q: QueryDensity,
    D: Send + Sync + 'static + Clone + AsRef<Q>,
@@ -256,7 +256,7 @@ pub fn multiexp<Q, D, G, S>(
    bases: S,
    density_map: D,
    exponents: Arc<Vec<<<G::Engine as ScalarEngine>::Fr as PrimeField>::Repr>>,
-) -> Box<Future<Item = <G as CurveAffine>::Projective, Error = SynthesisError>>
+) -> Box<dyn Future<Item = <G as CurveAffine>::Projective, Error = SynthesisError>>
 where
    for<'a> &'a Q: QueryDensity,
    D: Send + Sync + 'static + Clone + AsRef<Q>,
--- a/bellman/tests/mimc.rs
+++ b/bellman/tests/mimc.rs
@@ -1,8 +1,3 @@
 extern crate bellman;
 extern crate ff;
 extern crate pairing;
 extern crate rand;
 // For randomness (during paramgen and proof generation)
 use rand::thread_rng;
@@ -90,12 +85,12 @@ impl<'a, E: Engine> Circuit<E> for MiMCDemo<'a, E> {
            let cs = &mut cs.namespace(|| format!("round {}", i));
            // tmp = (xL + Ci)^2
-            let mut tmp_value = xl_value.map(|mut e| {
+            let tmp_value = xl_value.map(|mut e| {
                e.add_assign(&self.constants[i]);
                e.square();
                e
            });
-            let mut tmp = cs.alloc(
+            let tmp = cs.alloc(
                || "tmp",
                || tmp_value.ok_or(SynthesisError::AssignmentMissing),
            )?;
@@ -110,14 +105,14 @@ impl<'a, E: Engine> Circuit<E> for MiMCDemo<'a, E> {
            // new_xL = xR + (xL + Ci)^3
            // new_xL = xR + tmp * (xL + Ci)
            // new_xL - xR = tmp * (xL + Ci)
-            let mut new_xl_value = xl_value.map(|mut e| {
+            let new_xl_value = xl_value.map(|mut e| {
                e.add_assign(&self.constants[i]);
                e.mul_assign(&tmp_value.unwrap());
                e.add_assign(&xr_value.unwrap());
                e
            });
-            let mut new_xl = if i == (MIMC_ROUNDS - 1) {
+            let new_xl = if i == (MIMC_ROUNDS - 1) {
                // This is the last round, xL is our image and so
                // we allocate a public input.
                cs.alloc_input(
--- a/ff/Cargo.toml
+++ b/ff/Cargo.toml
@@ -1,18 +1,23 @@
 [package]
 name = "ff"
-version = "0.4.0"
+version = "0.5.2"
 authors = ["Sean Bowe <ewillbefull@gmail.com>"]
 description = "Library for building and interfacing with finite fields"
 readme = "README.md"
 documentation = "https://docs.rs/ff/"
 homepage = "https://github.com/ebfull/ff"
 license = "MIT/Apache-2.0"
 repository = "https://github.com/ebfull/ff"
 edition = "2018"
 [dependencies]
 byteorder = "1"
-ff_derive = { version = "0.3.0", path = "ff_derive", optional = true }
+ff_derive = { version = "^0.4.1", path = "ff_derive", optional = true }
 rand_core = "0.5"
 [features]
 default = []
 derive = ["ff_derive"]
 [badges]
 maintenance = { status = "actively-developed" }
--- a/ff/README.md
+++ b/ff/README.md
@@ -12,14 +12,18 @@ Add the `ff` crate to your `Cargo.toml`:
 ```toml
 [dependencies]
-ff = "0.4"
+ff = "0.5"
 ```
-The `ff` crate contains `Field`, `PrimeField`, `PrimeFieldRepr` and `SqrtField` traits. See the **[documentation](https://docs.rs/ff/0.4.0/ff/)** for more.
+The `ff` crate contains `Field`, `PrimeField`, `PrimeFieldRepr` and `SqrtField` traits.
 See the **[documentation](https://docs.rs/ff/)** for more.
 ### #![derive(PrimeField)]
-If you need an implementation of a prime field, this library also provides a procedural macro that will expand into an efficient implementation of a prime field when supplied with the modulus. `PrimeFieldGenerator` must be an element of Fp of p-1 order, that is also quadratic nonresidue.
+If you need an implementation of a prime field, this library also provides a procedural
 macro that will expand into an efficient implementation of a prime field when supplied
 with the modulus. `PrimeFieldGenerator` must be an element of Fp of p-1 order, that is
 also quadratic nonresidue.
 First, enable the `derive` crate feature:
@@ -41,13 +45,16 @@ extern crate ff;
 struct Fp(FpRepr);
 ```
-And that's it! `Fp` now implements `Field` and `PrimeField`. `Fp` will also implement `SqrtField` if supported. The library implements `FpRepr` itself and derives `PrimeFieldRepr` for it.
+And that's it! `Fp` now implements `Field` and `PrimeField`. `Fp` will also implement
 `SqrtField` if supported. The library implements `FpRepr` itself and derives
 `PrimeFieldRepr` for it.
 ## License
 Licensed under either of
- * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
--- a/ff/ff_derive/Cargo.toml
+++ b/ff/ff_derive/Cargo.toml
@@ -1,12 +1,13 @@
 [package]
 name = "ff_derive"
-version = "0.3.0"
+version = "0.4.1"
 authors = ["Sean Bowe <ewillbefull@gmail.com>"]
 description = "Procedural macro library used to build custom prime field implementations"
 documentation = "https://docs.rs/ff/"
 homepage = "https://github.com/ebfull/ff"
 license = "MIT/Apache-2.0"
 repository = "https://github.com/ebfull/ff"
 edition = "2018"
 [lib]
 proc-macro = true
@@ -15,6 +16,9 @@ proc-macro = true
 num-bigint = "0.2"
 num-traits = "0.2"
 num-integer = "0.1"
-proc-macro2 = "0.4"
+proc-macro2 = "1"
-quote = "0.6"
+quote = "1"
-syn = "0.14"
+syn = "1"
 [badges]
 maintenance = { status = "passively-maintained" }
--- a/ff/ff_derive/src/lib.rs
+++ b/ff/ff_derive/src/lib.rs
@@ -2,17 +2,11 @@
 extern crate proc_macro;
 extern crate proc_macro2;
 extern crate syn;
 #[macro_use]
 extern crate quote;
 extern crate num_bigint;
 extern crate num_integer;
 extern crate num_traits;
 use num_bigint::BigUint;
 use num_integer::Integer;
 use num_traits::{One, ToPrimitive, Zero};
 use quote::quote;
 use quote::TokenStreamExt;
 use std::str::FromStr;
@@ -91,10 +85,10 @@ fn fetch_wrapped_ident(body: &syn::Data) -> Option<syn::Ident> {
 /// Fetch an attribute string from the derived struct.
 fn fetch_attr(name: &str, attrs: &[syn::Attribute]) -> Option<String> {
    for attr in attrs {
-        if let Some(meta) = attr.interpret_meta() {
+        if let Ok(meta) = attr.parse_meta() {
            match meta {
                syn::Meta::NameValue(nv) => {
-                    if nv.ident.to_string() == name {
+                    if nv.path.get_ident().map(|i| i.to_string()) == Some(name.to_string()) {
                        match nv.lit {
                            syn::Lit::Str(ref s) => return Some(s.value()),
                            _ => {
@@ -122,9 +116,9 @@ fn prime_field_repr_impl(repr: &syn::Ident, limbs: usize) -> proc_macro2::TokenS
        impl ::std::fmt::Debug for #repr
        {
            fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
-                try!(write!(f, "0x"));
+                write!(f, "0x")?;
                for i in self.0.iter().rev() {
-                    try!(write!(f, "{:016x}", *i));
+                    write!(f, "{:016x}", *i)?;
                }
                Ok(())
@@ -133,9 +127,9 @@ fn prime_field_repr_impl(repr: &syn::Ident, limbs: usize) -> proc_macro2::TokenS
        impl ::std::fmt::Display for #repr {
            fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
-                try!(write!(f, "0x"));
+                write!(f, "0x")?;
                for i in self.0.iter().rev() {
-                    try!(write!(f, "{:016x}", *i));
+                    write!(f, "{:016x}", *i)?;
                }
                Ok(())
@@ -883,7 +877,7 @@ fn prime_field_impl(
        impl ::ff::Field for #name {
            /// Computes a uniformly random element using rejection sampling.
-            fn random<R: ::rand_core::RngCore>(rng: &mut R) -> Self {
+            fn random<R: ::rand_core::RngCore + ?std::marker::Sized>(rng: &mut R) -> Self {
                loop {
                    let mut tmp = {
                        let mut repr = [0u64; #limbs];
--- a/ff/src/lib.rs
+++ b/ff/src/lib.rs
@@ -1,12 +1,9 @@
 //! This crate provides traits for working with finite fields.
 // Catch documentation errors caused by code changes.
 #![deny(intra_doc_link_resolution_failure)]
 #![allow(unused_imports)]
 extern crate byteorder;
 extern crate rand_core;
 #[cfg(feature = "derive")]
 #[macro_use]
 extern crate ff_derive;
 #[cfg(feature = "derive")]
 pub use ff_derive::*;
@@ -20,7 +17,7 @@ pub trait Field:
    Sized + Eq + Copy + Clone + Send + Sync + fmt::Debug + fmt::Display + 'static
 {
    /// Returns an element chosen uniformly at random using a user-provided RNG.
-    fn random<R: RngCore>(rng: &mut R) -> Self;
+    fn random<R: RngCore + ?std::marker::Sized>(rng: &mut R) -> Self;
    /// Returns the zero element of the field, the additive identity.
    fn zero() -> Self;
@@ -210,7 +207,7 @@ impl Error for PrimeFieldDecodingError {
 }
 impl fmt::Display for PrimeFieldDecodingError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
        match *self {
            PrimeFieldDecodingError::NotInField(ref repr) => {
                write!(f, "{} is not an element of the field", repr)
@@ -266,7 +263,7 @@ pub trait PrimeField: Field {
    }
    /// Convert this prime field element into a biginteger representation.
-    fn from_repr(Self::Repr) -> Result<Self, PrimeFieldDecodingError>;
+    fn from_repr(_: Self::Repr) -> Result<Self, PrimeFieldDecodingError>;
    /// Convert a biginteger representation into a prime field element, if
    /// the number is an element of the field.
--- a/group/Cargo.toml
+++ b/group/Cargo.toml
@@ -1,18 +1,23 @@
 [package]
 name = "group"
-version = "0.1.0"
+version = "0.2.0"
 authors = [
    "Sean Bowe <ewillbefull@gmail.com>",
    "Jack Grigg <jack@z.cash>",
 ]
 readme = "README.md"
 license = "MIT/Apache-2.0"
 description = "Elliptic curve group traits and utilities"
 documentation = "https://docs.rs/group/"
 homepage = "https://github.com/ebfull/group"
 repository = "https://github.com/ebfull/group"
 edition = "2018"
 [dependencies]
-ff = { path = "../ff" }
+ff = { version = "0.5.0", path = "../ff" }
 rand = "0.7"
 rand_xorshift = "0.2"
 [badges]
 maintenance = { status = "actively-developed" }
--- a/group/README.md
+++ b/group/README.md
@@ -1,10 +1,13 @@
 # group [![Crates.io](https://img.shields.io/crates/v/group.svg)](https://crates.io/crates/group) #
 `group` is a crate for working with groups over elliptic curves.
 ## License
 Licensed under either of
- * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
--- a/group/src/lib.rs
+++ b/group/src/lib.rs
@@ -1,6 +1,5 @@
-extern crate ff;
+// Catch documentation errors caused by code changes.
-extern crate rand;
+#![deny(intra_doc_link_resolution_failure)]
 extern crate rand_xorshift;
 use ff::{PrimeField, PrimeFieldDecodingError, ScalarEngine, SqrtField};
 use rand::RngCore;
@@ -180,7 +179,7 @@ impl Error for GroupDecodingError {
 }
 impl fmt::Display for GroupDecodingError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
        match *self {
            GroupDecodingError::CoordinateDecodingError(description, ref err) => {
                write!(f, "{} decoding error: {}", description, err)
--- a/group/src/tests/mod.rs
+++ b/group/src/tests/mod.rs
@@ -2,7 +2,7 @@ use ff::{Field, PrimeField};
 use rand::SeedableRng;
 use rand_xorshift::XorShiftRng;
-use {CurveAffine, CurveProjective, EncodedPoint};
+use crate::{CurveAffine, CurveProjective, EncodedPoint};
 pub fn curve_tests<G: CurveProjective>() {
    let mut rng = XorShiftRng::from_seed([
@@ -71,7 +71,7 @@ pub fn curve_tests<G: CurveProjective>() {
 }
 fn random_wnaf_tests<G: CurveProjective>() {
-    use wnaf::*;
+    use crate::wnaf::*;
    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
--- a/librustzcash/Cargo.toml
+++ b/librustzcash/Cargo.toml
@@ -1,12 +1,18 @@
 [package]
 name = "librustzcash"
-version = "0.1.0"
+description = "Rust FFI used by the zcashd binary. Not an official API."
 version = "0.2.0"
 authors = [
    "Sean Bowe <ewillbefull@gmail.com>",
    "Jack Grigg <jack@z.cash>",
    "Jay Graber <jay@z.cash>",
    "Simon Liu <simon@z.cash>"
-    ]
+]
 homepage = "https://github.com/zcash/librustzcash"
 repository = "https://github.com/zcash/librustzcash"
 readme = "README.md"
 license = "MIT OR Apache-2.0"
 edition = "2018"
 [lib]
 name = "rustzcash"
@@ -14,15 +20,17 @@ path = "src/rustzcash.rs"
 crate-type = ["staticlib"]
 [dependencies]
-bellman = { path = "../bellman" }
+bellman = { version = "0.2.0", path = "../bellman" }
 blake2b_simd = "0.5"
 blake2s_simd = "0.5"
-ff = { path = "../ff" }
+ff = { version = "0.5.0", path = "../ff" }
 libc = "0.2"
-pairing = { path = "../pairing" }
+pairing = { version = "0.15.0", path = "../pairing" }
 lazy_static = "1"
-byteorder = "1"
+rand_core = "0.5.1"
-rand_core = "0.5"
+zcash_history = { version = "0.0.1", path = "../zcash_history" }
-rand_os = "0.2"
+zcash_primitives = { version = "0.1.0", path = "../zcash_primitives" }
-zcash_primitives = { path = "../zcash_primitives" }
+zcash_proofs = { version = "0.1.0", path = "../zcash_proofs" }
-zcash_proofs = { path = "../zcash_proofs" }
+
 [badges]
 maintenance = { status = "deprecated" }
--- a/librustzcash/README.md
+++ b/librustzcash/README.md
@@ -1,12 +1,17 @@
 # librustzcash
-This repository contains librustzcash, a static library for Zcash code assets written in Rust.
+`librustzcash` is an FFI library crate that exposes the Zcash Rust components to
 the `zcashd` full node.
 The FFI API does not have any stability guarantees, and will change as required
 by `zcashd`.
 ## License
 Licensed under either of
- * Apache License, Version 2.0, ([LICENSE-APACHE](../LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * Apache License, Version 2.0, ([LICENSE-APACHE](../LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](../LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
--- a/librustzcash/include/librustzcash.h
+++ b/librustzcash/include/librustzcash.h
@@ -112,8 +112,7 @@ extern "C" {
    bool librustzcash_sapling_output_proof(
        void *ctx,
        const unsigned char *esk,
-        const unsigned char *diversifier,
+        const unsigned char *payment_address,
        const unsigned char *pk_d,
        const unsigned char *rcm,
        const uint64_t value,
        unsigned char *cv,
@@ -308,6 +307,33 @@ extern "C" {
        unsigned char *j_ret,
        unsigned char *addr_ret
    );
    uint32_t librustzcash_mmr_append(
        uint32_t cbranch,
        uint32_t t_len,
        const uint32_t *ni_ptr,
        const unsigned char *n_ptr,
        size_t p_len,
        const unsigned char *nn_ptr,
        unsigned char *rt_ret,
        unsigned char *buf_ret
    );
    uint32_t librustzcash_mmr_delete(
        uint32_t cbranch,
        uint32_t t_len,
        const uint32_t *ni_ptr,
        const unsigned char *n_ptr,
        size_t p_len,
        size_t e_len,
        unsigned char *rt_ret
    );
    uint32_t librustzcash_mmr_hash_node(
        uint32_t cbranch,
        const unsigned char *n_ptr,
        unsigned char *h_ret
    );
 }
 #endif // LIBRUSTZCASH_INCLUDE_H_
--- a/librustzcash/src/rustzcash.rs
+++ b/librustzcash/src/rustzcash.rs
--- a/librustzcash/src/tests/key_agreement.rs
+++ b/librustzcash/src/tests/key_agreement.rs
@@ -1,11 +1,10 @@
 use ff::{PrimeField, PrimeFieldRepr};
 use pairing::bls12_381::Bls12;
-use rand_core::RngCore;
+use rand_core::{OsRng, RngCore};
 use rand_os::OsRng;
 use zcash_primitives::jubjub::{edwards, JubjubBls12};
 use zcash_primitives::primitives::{Diversifier, ViewingKey};
-use {
+use crate::{
    librustzcash_sapling_generate_r, librustzcash_sapling_ka_agree,
    librustzcash_sapling_ka_derivepublic,
 };
@@ -25,7 +24,7 @@ fn test_key_agreement() {
    let addr = loop {
        let mut d = [0; 11];
        rng.fill_bytes(&mut d);
-        match vk.into_payment_address(Diversifier(d), &params) {
+        match vk.to_payment_address(Diversifier(d), &params) {
            Some(a) => break a,
            None => {}
        }
@@ -47,7 +46,7 @@ fn test_key_agreement() {
    // Serialize pk_d for the call to librustzcash_sapling_ka_agree
    let mut addr_pk_d = [0u8; 32];
-    addr.pk_d.write(&mut addr_pk_d[..]).unwrap();
+    addr.pk_d().write(&mut addr_pk_d[..]).unwrap();
    assert!(librustzcash_sapling_ka_agree(
        &addr_pk_d,
@@ -59,7 +58,7 @@ fn test_key_agreement() {
    // using the diversifier and esk.
    let mut epk = [0u8; 32];
    assert!(librustzcash_sapling_ka_derivepublic(
-        &addr.diversifier.0,
+        &addr.diversifier().0,
        &esk,
        &mut epk
    ));
--- a/librustzcash/src/tests/key_components.rs
+++ b/librustzcash/src/tests/key_components.rs
@@ -7,7 +7,7 @@ use zcash_primitives::{
 use super::JUBJUB;
-use {
+use crate::{
    librustzcash_ask_to_ak, librustzcash_check_diversifier, librustzcash_crh_ivk,
    librustzcash_ivk_to_pkd, librustzcash_nsk_to_nk,
 };
@@ -678,7 +678,7 @@ fn key_components() {
        }
        let pgk = ProofGenerationKey { ak, nsk };
-        let fvk = pgk.into_viewing_key(&JUBJUB);
+        let fvk = pgk.to_viewing_key(&JUBJUB);
        {
            let mut vec = Vec::new();
            fvk.nk.write(&mut vec).unwrap();
@@ -704,10 +704,10 @@ fn key_components() {
        let diversifier = Diversifier(tv.default_d);
        assert!(librustzcash_check_diversifier(&tv.default_d));
-        let addr = fvk.into_payment_address(diversifier, &JUBJUB).unwrap();
+        let addr = fvk.to_payment_address(diversifier, &JUBJUB).unwrap();
        {
            let mut vec = Vec::new();
-            addr.pk_d.write(&mut vec).unwrap();
+            addr.pk_d().write(&mut vec).unwrap();
            assert_eq!(&vec, &tv.default_pk_d);
        }
        {
--- a/librustzcash/src/tests/mmr.rs
+++ b/librustzcash/src/tests/mmr.rs
@@ -0,0 +1,225 @@
 use zcash_history::{Entry, EntryLink, NodeData};
 use crate::{librustzcash_mmr_append, librustzcash_mmr_delete};
 const NODE_DATA_16L: &[u8] = include_bytes!("./res/tree16.dat");
 const NODE_DATA_1023L: &[u8] = include_bytes!("./res/tree1023.dat");
 struct TreeView {
    peaks: Vec<(u32, Entry)>,
    extra: Vec<(u32, Entry)>,
 }
 fn draft(into: &mut Vec<(u32, Entry)>, nodes: &[NodeData], peak_pos: usize, h: u32) {
    let node_data = nodes[peak_pos - 1].clone();
    let peak: Entry = match h {
        0 => node_data.into(),
        _ => Entry::new(
            node_data,
            EntryLink::Stored((peak_pos - (1 << h) - 1) as u32),
            EntryLink::Stored((peak_pos - 2) as u32),
        ),
    };
    into.push(((peak_pos - 1) as u32, peak));
 }
 fn prepare_tree(nodes: &[NodeData]) -> TreeView {
    assert!(!nodes.is_empty());
    // integer log2 of (nodes.len()+1), -1
    let mut h = (32 - ((nodes.len() + 1) as u32).leading_zeros() - 1) - 1;
    let mut peak_pos = (1 << (h + 1)) - 1;
    let mut peaks = Vec::new();
    // used later
    let mut last_peak_pos = 0;
    let mut last_peak_h = 0;
    loop {
        if peak_pos > nodes.len() {
            // left child, -2^h
            peak_pos -= 1 << h;
            h -= 1;
        }
        if peak_pos <= nodes.len() {
            draft(&mut peaks, nodes, peak_pos, h);
            // save to be used in next loop
            last_peak_pos = peak_pos;
            last_peak_h = h;
            // right sibling
            peak_pos += (1 << (h + 1)) - 1;
        }
        if h == 0 {
            break;
        }
    }
    // for deletion, everything on the right slope of the last peak should be pre-loaded
    let mut extra = Vec::new();
    let mut h = last_peak_h;
    let mut peak_pos = last_peak_pos;
    while h > 0 {
        let left_pos = peak_pos - (1 << h);
        let right_pos = peak_pos - 1;
        h -= 1;
        // drafting left child
        draft(&mut extra, nodes, left_pos, h);
        // drafting right child
        draft(&mut extra, nodes, right_pos, h);
        // continuing on right slope
        peak_pos = right_pos;
    }
    TreeView { peaks, extra }
 }
 fn preload_tree_append(nodes: &[NodeData]) -> (Vec<u32>, Vec<[u8; zcash_history::MAX_ENTRY_SIZE]>) {
    assert!(!nodes.is_empty());
    let tree_view = prepare_tree(nodes);
    let mut indices = Vec::new();
    let mut bytes = Vec::new();
    for (idx, entry) in tree_view.peaks.into_iter() {
        let mut buf = [0u8; zcash_history::MAX_ENTRY_SIZE];
        entry
            .write(&mut &mut buf[..])
            .expect("Cannot fail if enough buffer length");
        indices.push(idx);
        bytes.push(buf);
    }
    (indices, bytes)
 }
 // also returns number of peaks
 fn preload_tree_delete(
    nodes: &[NodeData],
 ) -> (Vec<u32>, Vec<[u8; zcash_history::MAX_ENTRY_SIZE]>, usize) {
    assert!(!nodes.is_empty());
    let tree_view = prepare_tree(nodes);
    let mut indices = Vec::new();
    let mut bytes = Vec::new();
    let peak_count = tree_view.peaks.len();
    for (idx, entry) in tree_view
        .peaks
        .into_iter()
        .chain(tree_view.extra.into_iter())
    {
        let mut buf = [0u8; zcash_history::MAX_ENTRY_SIZE];
        entry
            .write(&mut &mut buf[..])
            .expect("Cannot fail if enough buffer length");
        indices.push(idx);
        bytes.push(buf);
    }
    (indices, bytes, peak_count)
 }
 fn load_nodes(bytes: &'static [u8]) -> Vec<NodeData> {
    let mut res = Vec::new();
    let mut cursor = std::io::Cursor::new(bytes);
    while (cursor.position() as usize) < bytes.len() {
        let node_data = zcash_history::NodeData::read(0, &mut cursor)
            .expect("Statically checked to be correct");
        res.push(node_data);
    }
    res
 }
 #[test]
 fn append() {
    let nodes = load_nodes(NODE_DATA_16L);
    let (indices, peaks) = preload_tree_append(&nodes);
    let mut rt_ret = [0u8; 32];
    let mut buf_ret = Vec::<[u8; zcash_history::MAX_NODE_DATA_SIZE]>::with_capacity(32);
    let mut new_node_data = [0u8; zcash_history::MAX_NODE_DATA_SIZE];
    let new_node = NodeData {
        consensus_branch_id: 0,
        subtree_commitment: [0u8; 32],
        start_time: 101,
        end_time: 110,
        start_target: 190,
        end_target: 200,
        start_sapling_root: [0u8; 32],
        end_sapling_root: [0u8; 32],
        subtree_total_work: Default::default(),
        start_height: 10,
        end_height: 10,
        sapling_tx: 13,
    };
    new_node
        .write(&mut &mut new_node_data[..])
        .expect("Failed to write node data");
    let result = librustzcash_mmr_append(
        0,
        nodes.len() as u32,
        indices.as_ptr(),
        peaks.as_ptr(),
        peaks.len(),
        &new_node_data,
        &mut rt_ret,
        buf_ret.as_mut_ptr(),
    );
    unsafe {
        buf_ret.set_len(result as usize);
    }
    assert_eq!(result, 2);
    let new_node_1 =
        NodeData::from_bytes(0, &buf_ret[0][..]).expect("Failed to reconstruct return node #1");
    let new_node_2 =
        NodeData::from_bytes(0, &buf_ret[1][..]).expect("Failed to reconstruct return node #2");
    assert_eq!(new_node_1.start_height, 10);
    assert_eq!(new_node_1.end_height, 10);
    // this is combined new node (which is `new_node_1`) + the one which was there before (for block #9)
    assert_eq!(new_node_2.start_height, 9);
    assert_eq!(new_node_2.end_height, 10);
    assert_eq!(new_node_2.sapling_tx, 27);
 }
 #[test]
 fn delete() {
    let nodes = load_nodes(NODE_DATA_1023L);
    let (indices, nodes, peak_count) = preload_tree_delete(&nodes);
    let mut rt_ret = [0u8; 32];
    let result = librustzcash_mmr_delete(
        0,
        nodes.len() as u32,
        indices.as_ptr(),
        nodes.as_ptr(),
        peak_count,
        indices.len() - peak_count,
        &mut rt_ret,
    );
    // Deleting from full tree of 9 height would result in cascade deleting of 10 nodes
    assert_eq!(result, 10);
 }
--- a/librustzcash/src/tests/mod.rs
+++ b/librustzcash/src/tests/mod.rs
@@ -4,6 +4,7 @@ use super::JUBJUB;
 mod key_agreement;
 mod key_components;
 mod mmr;
 mod notes;
 mod signatures;
--- a/librustzcash/src/tests/notes.rs
+++ b/librustzcash/src/tests/notes.rs
@@ -1,5 +1,5 @@
-use librustzcash_sapling_compute_cm;
+use crate::librustzcash_sapling_compute_cm;
-use librustzcash_sapling_compute_nf;
+use crate::librustzcash_sapling_compute_nf;
 #[test]
 fn notes() {
--- a/librustzcash/src/tests/res/tree1023.dat
+++ b/librustzcash/src/tests/res/tree1023.dat
--- a/librustzcash/src/tests/res/tree16.dat
+++ b/librustzcash/src/tests/res/tree16.dat
--- a/pairing/Cargo.toml
+++ b/pairing/Cargo.toml
@@ -2,22 +2,24 @@
 name = "pairing"
 # Remember to change version string in README.md.
-version = "0.14.2"
+version = "0.15.1"
 authors = [
    "Sean Bowe <ewillbefull@gmail.com>",
    "Jack Grigg <jack@z.cash>",
 ]
 readme = "README.md"
 license = "MIT/Apache-2.0"
 description = "Pairing-friendly elliptic curve library"
 documentation = "https://docs.rs/pairing/"
 homepage = "https://github.com/ebfull/pairing"
 repository = "https://github.com/ebfull/pairing"
 edition ="2018"
 [dependencies]
 byteorder = "1"
-ff = { path = "../ff", features = ["derive"] }
+ff = { version = "^0.5.2", path = "../ff", features = ["derive"] }
-group = { path = "../group" }
+group = { version = "0.2.0", path = "../group" }
 rand_core = "0.5"
 [dev-dependencies]
@@ -27,3 +29,6 @@ rand_xorshift = "0.2"
 unstable-features = ["expose-arith"]
 expose-arith = []
 default = []
 [badges]
 maintenance = { status = "actively-developed" }
--- a/pairing/README.md
+++ b/pairing/README.md
@@ -1,6 +1,16 @@
 # pairing [![Crates.io](https://img.shields.io/crates/v/pairing.svg)](https://crates.io/crates/pairing) #
-This is a Rust crate for using pairing-friendly elliptic curves. Currently, only the [BLS12-381](https://z.cash/blog/new-snark-curve.html) construction is implemented.
+`pairing` is a crate for using pairing-friendly elliptic curves.
 Currently, only the [BLS12-381](https://z.cash/blog/new-snark-curve.html)
 construction is implemented.
 ## Roadmap
 `pairing` is being refactored into a generic library for working with
 pairing-friendly curves. After the refactor, `pairing` will provide basic traits
 for pairing-friendly elliptic curve constructions, while specific curves will be
 in separate crates.
 ## [Documentation](https://docs.rs/pairing/)
@@ -8,13 +18,15 @@ Bring the `pairing` crate into your project just as you normally would.
 ## Security Warnings
-This library does not make any guarantees about constant-time operations, memory access patterns, or resistance to side-channel attacks.
+This library does not make any guarantees about constant-time operations, memory
 access patterns, or resistance to side-channel attacks.
 ## License
 Licensed under either of
- * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
--- a/pairing/benches/bls12_381/ec.rs
+++ b/pairing/benches/bls12_381/ec.rs
@@ -1,6 +1,8 @@
 mod g1 {
-    use rand::{Rand, SeedableRng, XorShiftRng};
+    use rand_core::SeedableRng;
    use rand_xorshift::XorShiftRng;
    use ff::Field;
    use group::CurveProjective;
    use pairing::bls12_381::*;
@@ -8,10 +10,13 @@ mod g1 {
    fn bench_g1_mul_assign(b: &mut ::test::Bencher) {
        const SAMPLES: usize = 1000;
-        let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let v: Vec<(G1, Fr)> = (0..SAMPLES)
-            .map(|_| (G1::rand(&mut rng), Fr::rand(&mut rng)))
+            .map(|_| (G1::random(&mut rng), Fr::random(&mut rng)))
            .collect();
        let mut count = 0;
@@ -27,10 +32,13 @@ mod g1 {
    fn bench_g1_add_assign(b: &mut ::test::Bencher) {
        const SAMPLES: usize = 1000;
-        let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let v: Vec<(G1, G1)> = (0..SAMPLES)
-            .map(|_| (G1::rand(&mut rng), G1::rand(&mut rng)))
+            .map(|_| (G1::random(&mut rng), G1::random(&mut rng)))
            .collect();
        let mut count = 0;
@@ -46,10 +54,13 @@ mod g1 {
    fn bench_g1_add_assign_mixed(b: &mut ::test::Bencher) {
        const SAMPLES: usize = 1000;
-        let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let v: Vec<(G1, G1Affine)> = (0..SAMPLES)
-            .map(|_| (G1::rand(&mut rng), G1::rand(&mut rng).into()))
+            .map(|_| (G1::random(&mut rng), G1::random(&mut rng).into()))
            .collect();
        let mut count = 0;
@@ -63,8 +74,10 @@ mod g1 {
 }
 mod g2 {
-    use rand::{Rand, SeedableRng, XorShiftRng};
+    use rand_core::SeedableRng;
    use rand_xorshift::XorShiftRng;
    use ff::Field;
    use group::CurveProjective;
    use pairing::bls12_381::*;
@@ -72,10 +85,13 @@ mod g2 {
    fn bench_g2_mul_assign(b: &mut ::test::Bencher) {
        const SAMPLES: usize = 1000;
-        let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let v: Vec<(G2, Fr)> = (0..SAMPLES)
-            .map(|_| (G2::rand(&mut rng), Fr::rand(&mut rng)))
+            .map(|_| (G2::random(&mut rng), Fr::random(&mut rng)))
            .collect();
        let mut count = 0;
@@ -91,10 +107,13 @@ mod g2 {
    fn bench_g2_add_assign(b: &mut ::test::Bencher) {
        const SAMPLES: usize = 1000;
-        let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let v: Vec<(G2, G2)> = (0..SAMPLES)
-            .map(|_| (G2::rand(&mut rng), G2::rand(&mut rng)))
+            .map(|_| (G2::random(&mut rng), G2::random(&mut rng)))
            .collect();
        let mut count = 0;
@@ -110,10 +129,13 @@ mod g2 {
    fn bench_g2_add_assign_mixed(b: &mut ::test::Bencher) {
        const SAMPLES: usize = 1000;
-        let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+        let mut rng = XorShiftRng::from_seed([
            0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06,
            0xbc, 0xe5,
        ]);
        let v: Vec<(G2, G2Affine)> = (0..SAMPLES)
-            .map(|_| (G2::rand(&mut rng), G2::rand(&mut rng).into()))
+            .map(|_| (G2::random(&mut rng), G2::random(&mut rng).into()))
            .collect();
        let mut count = 0;
--- a/pairing/benches/bls12_381/fq.rs
+++ b/pairing/benches/bls12_381/fq.rs
@@ -1,4 +1,5 @@
-use rand::{Rand, SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
 use rand_xorshift::XorShiftRng;
 use ff::{Field, PrimeField, PrimeFieldRepr, SqrtField};
 use pairing::bls12_381::*;
@@ -7,12 +8,15 @@ use pairing::bls12_381::*;
 fn bench_fq_repr_add_nocarry(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(FqRepr, FqRepr)> = (0..SAMPLES)
        .map(|_| {
-            let mut tmp1 = FqRepr::rand(&mut rng);
+            let mut tmp1 = Fq::random(&mut rng).into_repr();
-            let mut tmp2 = FqRepr::rand(&mut rng);
+            let mut tmp2 = Fq::random(&mut rng).into_repr();
            // Shave a few bits off to avoid overflow.
            for _ in 0..3 {
                tmp1.div2();
@@ -35,11 +39,14 @@ fn bench_fq_repr_add_nocarry(b: &mut ::test::Bencher) {
 fn bench_fq_repr_sub_noborrow(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(FqRepr, FqRepr)> = (0..SAMPLES)
        .map(|_| {
-            let tmp1 = FqRepr::rand(&mut rng);
+            let tmp1 = Fq::random(&mut rng).into_repr();
            let mut tmp2 = tmp1;
            // Ensure tmp2 is smaller than tmp1.
            for _ in 0..10 {
@@ -62,9 +69,14 @@ fn bench_fq_repr_sub_noborrow(b: &mut ::test::Bencher) {
 fn bench_fq_repr_num_bits(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<FqRepr> = (0..SAMPLES).map(|_| FqRepr::rand(&mut rng)).collect();
+    let v: Vec<FqRepr> = (0..SAMPLES)
        .map(|_| Fq::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
    b.iter(|| {
@@ -78,9 +90,14 @@ fn bench_fq_repr_num_bits(b: &mut ::test::Bencher) {
 fn bench_fq_repr_mul2(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<FqRepr> = (0..SAMPLES).map(|_| FqRepr::rand(&mut rng)).collect();
+    let v: Vec<FqRepr> = (0..SAMPLES)
        .map(|_| Fq::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
    b.iter(|| {
@@ -95,9 +112,14 @@ fn bench_fq_repr_mul2(b: &mut ::test::Bencher) {
 fn bench_fq_repr_div2(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<FqRepr> = (0..SAMPLES).map(|_| FqRepr::rand(&mut rng)).collect();
+    let v: Vec<FqRepr> = (0..SAMPLES)
        .map(|_| Fq::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
    b.iter(|| {
@@ -112,10 +134,13 @@ fn bench_fq_repr_div2(b: &mut ::test::Bencher) {
 fn bench_fq_add_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq, Fq)> = (0..SAMPLES)
-        .map(|_| (Fq::rand(&mut rng), Fq::rand(&mut rng)))
+        .map(|_| (Fq::random(&mut rng), Fq::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -131,10 +156,13 @@ fn bench_fq_add_assign(b: &mut ::test::Bencher) {
 fn bench_fq_sub_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq, Fq)> = (0..SAMPLES)
-        .map(|_| (Fq::rand(&mut rng), Fq::rand(&mut rng)))
+        .map(|_| (Fq::random(&mut rng), Fq::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -150,10 +178,13 @@ fn bench_fq_sub_assign(b: &mut ::test::Bencher) {
 fn bench_fq_mul_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq, Fq)> = (0..SAMPLES)
-        .map(|_| (Fq::rand(&mut rng), Fq::rand(&mut rng)))
+        .map(|_| (Fq::random(&mut rng), Fq::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -169,9 +200,12 @@ fn bench_fq_mul_assign(b: &mut ::test::Bencher) {
 fn bench_fq_square(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::rand(&mut rng)).collect();
+    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -186,9 +220,12 @@ fn bench_fq_square(b: &mut ::test::Bencher) {
 fn bench_fq_inverse(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::rand(&mut rng)).collect();
+    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -201,9 +238,12 @@ fn bench_fq_inverse(b: &mut ::test::Bencher) {
 fn bench_fq_negate(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::rand(&mut rng)).collect();
+    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -218,11 +258,14 @@ fn bench_fq_negate(b: &mut ::test::Bencher) {
 fn bench_fq_sqrt(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<Fq> = (0..SAMPLES)
        .map(|_| {
-            let mut tmp = Fq::rand(&mut rng);
+            let mut tmp = Fq::random(&mut rng);
            tmp.square();
            tmp
        })
@@ -239,9 +282,12 @@ fn bench_fq_sqrt(b: &mut ::test::Bencher) {
 fn bench_fq_into_repr(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::rand(&mut rng)).collect();
+    let v: Vec<Fq> = (0..SAMPLES).map(|_| Fq::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -254,10 +300,13 @@ fn bench_fq_into_repr(b: &mut ::test::Bencher) {
 fn bench_fq_from_repr(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<FqRepr> = (0..SAMPLES)
-        .map(|_| Fq::rand(&mut rng).into_repr())
+        .map(|_| Fq::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
--- a/pairing/benches/bls12_381/fq12.rs
+++ b/pairing/benches/bls12_381/fq12.rs
@@ -1,4 +1,5 @@
-use rand::{Rand, SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
 use rand_xorshift::XorShiftRng;
 use ff::Field;
 use pairing::bls12_381::*;
@@ -7,10 +8,13 @@ use pairing::bls12_381::*;
 fn bench_fq12_add_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq12, Fq12)> = (0..SAMPLES)
-        .map(|_| (Fq12::rand(&mut rng), Fq12::rand(&mut rng)))
+        .map(|_| (Fq12::random(&mut rng), Fq12::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -26,10 +30,13 @@ fn bench_fq12_add_assign(b: &mut ::test::Bencher) {
 fn bench_fq12_sub_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq12, Fq12)> = (0..SAMPLES)
-        .map(|_| (Fq12::rand(&mut rng), Fq12::rand(&mut rng)))
+        .map(|_| (Fq12::random(&mut rng), Fq12::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -45,10 +52,13 @@ fn bench_fq12_sub_assign(b: &mut ::test::Bencher) {
 fn bench_fq12_mul_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq12, Fq12)> = (0..SAMPLES)
-        .map(|_| (Fq12::rand(&mut rng), Fq12::rand(&mut rng)))
+        .map(|_| (Fq12::random(&mut rng), Fq12::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -64,9 +74,12 @@ fn bench_fq12_mul_assign(b: &mut ::test::Bencher) {
 fn bench_fq12_squaring(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq12> = (0..SAMPLES).map(|_| Fq12::rand(&mut rng)).collect();
+    let v: Vec<Fq12> = (0..SAMPLES).map(|_| Fq12::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -81,9 +94,12 @@ fn bench_fq12_squaring(b: &mut ::test::Bencher) {
 fn bench_fq12_inverse(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq12> = (0..SAMPLES).map(|_| Fq12::rand(&mut rng)).collect();
+    let v: Vec<Fq12> = (0..SAMPLES).map(|_| Fq12::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
--- a/pairing/benches/bls12_381/fq2.rs
+++ b/pairing/benches/bls12_381/fq2.rs
@@ -1,4 +1,5 @@
-use rand::{Rand, SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
 use rand_xorshift::XorShiftRng;
 use ff::{Field, SqrtField};
 use pairing::bls12_381::*;
@@ -7,10 +8,13 @@ use pairing::bls12_381::*;
 fn bench_fq2_add_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq2, Fq2)> = (0..SAMPLES)
-        .map(|_| (Fq2::rand(&mut rng), Fq2::rand(&mut rng)))
+        .map(|_| (Fq2::random(&mut rng), Fq2::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -26,10 +30,13 @@ fn bench_fq2_add_assign(b: &mut ::test::Bencher) {
 fn bench_fq2_sub_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq2, Fq2)> = (0..SAMPLES)
-        .map(|_| (Fq2::rand(&mut rng), Fq2::rand(&mut rng)))
+        .map(|_| (Fq2::random(&mut rng), Fq2::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -45,10 +52,13 @@ fn bench_fq2_sub_assign(b: &mut ::test::Bencher) {
 fn bench_fq2_mul_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fq2, Fq2)> = (0..SAMPLES)
-        .map(|_| (Fq2::rand(&mut rng), Fq2::rand(&mut rng)))
+        .map(|_| (Fq2::random(&mut rng), Fq2::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -64,9 +74,12 @@ fn bench_fq2_mul_assign(b: &mut ::test::Bencher) {
 fn bench_fq2_squaring(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq2> = (0..SAMPLES).map(|_| Fq2::rand(&mut rng)).collect();
+    let v: Vec<Fq2> = (0..SAMPLES).map(|_| Fq2::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -81,9 +94,12 @@ fn bench_fq2_squaring(b: &mut ::test::Bencher) {
 fn bench_fq2_inverse(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq2> = (0..SAMPLES).map(|_| Fq2::rand(&mut rng)).collect();
+    let v: Vec<Fq2> = (0..SAMPLES).map(|_| Fq2::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -97,9 +113,12 @@ fn bench_fq2_inverse(b: &mut ::test::Bencher) {
 fn bench_fq2_sqrt(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fq2> = (0..SAMPLES).map(|_| Fq2::rand(&mut rng)).collect();
+    let v: Vec<Fq2> = (0..SAMPLES).map(|_| Fq2::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
--- a/pairing/benches/bls12_381/fr.rs
+++ b/pairing/benches/bls12_381/fr.rs
@@ -1,4 +1,5 @@
-use rand::{Rand, SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
 use rand_xorshift::XorShiftRng;
 use ff::{Field, PrimeField, PrimeFieldRepr, SqrtField};
 use pairing::bls12_381::*;
@@ -7,12 +8,15 @@ use pairing::bls12_381::*;
 fn bench_fr_repr_add_nocarry(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(FrRepr, FrRepr)> = (0..SAMPLES)
        .map(|_| {
-            let mut tmp1 = FrRepr::rand(&mut rng);
+            let mut tmp1 = Fr::random(&mut rng).into_repr();
-            let mut tmp2 = FrRepr::rand(&mut rng);
+            let mut tmp2 = Fr::random(&mut rng).into_repr();
            // Shave a few bits off to avoid overflow.
            for _ in 0..3 {
                tmp1.div2();
@@ -35,11 +39,14 @@ fn bench_fr_repr_add_nocarry(b: &mut ::test::Bencher) {
 fn bench_fr_repr_sub_noborrow(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(FrRepr, FrRepr)> = (0..SAMPLES)
        .map(|_| {
-            let tmp1 = FrRepr::rand(&mut rng);
+            let tmp1 = Fr::random(&mut rng).into_repr();
            let mut tmp2 = tmp1;
            // Ensure tmp2 is smaller than tmp1.
            for _ in 0..10 {
@@ -62,9 +69,14 @@ fn bench_fr_repr_sub_noborrow(b: &mut ::test::Bencher) {
 fn bench_fr_repr_num_bits(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<FrRepr> = (0..SAMPLES).map(|_| FrRepr::rand(&mut rng)).collect();
+    let v: Vec<FrRepr> = (0..SAMPLES)
        .map(|_| Fr::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
    b.iter(|| {
@@ -78,9 +90,14 @@ fn bench_fr_repr_num_bits(b: &mut ::test::Bencher) {
 fn bench_fr_repr_mul2(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<FrRepr> = (0..SAMPLES).map(|_| FrRepr::rand(&mut rng)).collect();
+    let v: Vec<FrRepr> = (0..SAMPLES)
        .map(|_| Fr::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
    b.iter(|| {
@@ -95,9 +112,14 @@ fn bench_fr_repr_mul2(b: &mut ::test::Bencher) {
 fn bench_fr_repr_div2(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<FrRepr> = (0..SAMPLES).map(|_| FrRepr::rand(&mut rng)).collect();
+    let v: Vec<FrRepr> = (0..SAMPLES)
        .map(|_| Fr::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
    b.iter(|| {
@@ -112,10 +134,13 @@ fn bench_fr_repr_div2(b: &mut ::test::Bencher) {
 fn bench_fr_add_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fr, Fr)> = (0..SAMPLES)
-        .map(|_| (Fr::rand(&mut rng), Fr::rand(&mut rng)))
+        .map(|_| (Fr::random(&mut rng), Fr::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -131,10 +156,13 @@ fn bench_fr_add_assign(b: &mut ::test::Bencher) {
 fn bench_fr_sub_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fr, Fr)> = (0..SAMPLES)
-        .map(|_| (Fr::rand(&mut rng), Fr::rand(&mut rng)))
+        .map(|_| (Fr::random(&mut rng), Fr::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -150,10 +178,13 @@ fn bench_fr_sub_assign(b: &mut ::test::Bencher) {
 fn bench_fr_mul_assign(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(Fr, Fr)> = (0..SAMPLES)
-        .map(|_| (Fr::rand(&mut rng), Fr::rand(&mut rng)))
+        .map(|_| (Fr::random(&mut rng), Fr::random(&mut rng)))
        .collect();
    let mut count = 0;
@@ -169,9 +200,12 @@ fn bench_fr_mul_assign(b: &mut ::test::Bencher) {
 fn bench_fr_square(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::rand(&mut rng)).collect();
+    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -186,9 +220,12 @@ fn bench_fr_square(b: &mut ::test::Bencher) {
 fn bench_fr_inverse(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::rand(&mut rng)).collect();
+    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -201,9 +238,12 @@ fn bench_fr_inverse(b: &mut ::test::Bencher) {
 fn bench_fr_negate(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::rand(&mut rng)).collect();
+    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -218,11 +258,14 @@ fn bench_fr_negate(b: &mut ::test::Bencher) {
 fn bench_fr_sqrt(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<Fr> = (0..SAMPLES)
        .map(|_| {
-            let mut tmp = Fr::rand(&mut rng);
+            let mut tmp = Fr::random(&mut rng);
            tmp.square();
            tmp
        })
@@ -239,9 +282,12 @@ fn bench_fr_sqrt(b: &mut ::test::Bencher) {
 fn bench_fr_into_repr(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::rand(&mut rng)).collect();
+    let v: Vec<Fr> = (0..SAMPLES).map(|_| Fr::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -254,10 +300,13 @@ fn bench_fr_into_repr(b: &mut ::test::Bencher) {
 fn bench_fr_from_repr(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<FrRepr> = (0..SAMPLES)
-        .map(|_| Fr::rand(&mut rng).into_repr())
+        .map(|_| Fr::random(&mut rng).into_repr())
        .collect();
    let mut count = 0;
--- a/pairing/benches/bls12_381/mod.rs
+++ b/pairing/benches/bls12_381/mod.rs
@@ -4,8 +4,10 @@ mod fq12;
 mod fq2;
 mod fr;
-use rand::{Rand, SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
 use rand_xorshift::XorShiftRng;
 use group::CurveProjective;
 use pairing::bls12_381::*;
 use pairing::{Engine, PairingCurveAffine};
@@ -13,9 +15,12 @@ use pairing::{Engine, PairingCurveAffine};
 fn bench_pairing_g1_preparation(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<G1> = (0..SAMPLES).map(|_| G1::rand(&mut rng)).collect();
+    let v: Vec<G1> = (0..SAMPLES).map(|_| G1::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -29,9 +34,12 @@ fn bench_pairing_g1_preparation(b: &mut ::test::Bencher) {
 fn bench_pairing_g2_preparation(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
-    let v: Vec<G2> = (0..SAMPLES).map(|_| G2::rand(&mut rng)).collect();
+    let v: Vec<G2> = (0..SAMPLES).map(|_| G2::random(&mut rng)).collect();
    let mut count = 0;
    b.iter(|| {
@@ -45,13 +53,16 @@ fn bench_pairing_g2_preparation(b: &mut ::test::Bencher) {
 fn bench_pairing_miller_loop(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(G1Prepared, G2Prepared)> = (0..SAMPLES)
        .map(|_| {
            (
-                G1Affine::from(G1::rand(&mut rng)).prepare(),
+                G1Affine::from(G1::random(&mut rng)).prepare(),
-                G2Affine::from(G2::rand(&mut rng)).prepare(),
+                G2Affine::from(G2::random(&mut rng)).prepare(),
            )
        })
        .collect();
@@ -68,13 +79,16 @@ fn bench_pairing_miller_loop(b: &mut ::test::Bencher) {
 fn bench_pairing_final_exponentiation(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<Fq12> = (0..SAMPLES)
        .map(|_| {
            (
-                G1Affine::from(G1::rand(&mut rng)).prepare(),
+                G1Affine::from(G1::random(&mut rng)).prepare(),
-                G2Affine::from(G2::rand(&mut rng)).prepare(),
+                G2Affine::from(G2::random(&mut rng)).prepare(),
            )
        })
        .map(|(ref p, ref q)| Bls12::miller_loop(&[(p, q)]))
@@ -92,10 +106,13 @@ fn bench_pairing_final_exponentiation(b: &mut ::test::Bencher) {
 fn bench_pairing_full(b: &mut ::test::Bencher) {
    const SAMPLES: usize = 1000;
-    let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+    let mut rng = XorShiftRng::from_seed([
        0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37, 0x32, 0x54, 0x06, 0xbc,
        0xe5,
    ]);
    let v: Vec<(G1, G2)> = (0..SAMPLES)
-        .map(|_| (G1::rand(&mut rng), G2::rand(&mut rng)))
+        .map(|_| (G1::random(&mut rng), G2::random(&mut rng)))
        .collect();
    let mut count = 0;
--- a/pairing/benches/pairing_benches.rs
+++ b/pairing/benches/pairing_benches.rs
@@ -3,7 +3,8 @@
 extern crate ff;
 extern crate group;
 extern crate pairing;
-extern crate rand;
+extern crate rand_core;
 extern crate rand_xorshift;
 extern crate test;
 mod bls12_381;
--- a/pairing/src/bls12_381/ec.rs
+++ b/pairing/src/bls12_381/ec.rs
@@ -18,7 +18,7 @@ macro_rules! curve_impl {
        }
        impl ::std::fmt::Display for $affine {
-            fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
                if self.infinity {
                    write!(f, "{}(Infinity)", $name)
                } else {
@@ -35,7 +35,7 @@ macro_rules! curve_impl {
        }
        impl ::std::fmt::Display for $projective {
-            fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
                write!(f, "{}", self.into_affine())
            }
        }
@@ -200,7 +200,7 @@ macro_rules! curve_impl {
            type Base = $basefield;
            type Affine = $affine;
-            fn random<R: RngCore>(rng: &mut R) -> Self {
+            fn random<R: RngCore + ?std::marker::Sized>(rng: &mut R) -> Self {
                loop {
                    let x = $basefield::random(rng);
                    let greatest = rng.next_u32() % 2 != 0;
@@ -622,11 +622,11 @@ macro_rules! curve_impl {
 pub mod g1 {
    use super::super::{Bls12, Fq, Fq12, FqRepr, Fr, FrRepr};
    use super::g2::G2Affine;
    use crate::{Engine, PairingCurveAffine};
    use ff::{BitIterator, Field, PrimeField, PrimeFieldRepr, SqrtField};
    use group::{CurveAffine, CurveProjective, EncodedPoint, GroupDecodingError};
    use rand_core::RngCore;
    use std::fmt;
    use {Engine, PairingCurveAffine};
    curve_impl!(
        "G1",
@@ -656,7 +656,7 @@ pub mod g1 {
    }
    impl fmt::Debug for G1Uncompressed {
-        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
            self.0[..].fmt(formatter)
        }
    }
@@ -766,7 +766,7 @@ pub mod g1 {
    }
    impl fmt::Debug for G1Compressed {
-        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
            self.0[..].fmt(formatter)
        }
    }
@@ -934,7 +934,7 @@ pub mod g1 {
    #[test]
    fn g1_generator() {
-        use SqrtField;
+        use crate::SqrtField;
        let mut x = Fq::zero();
        let mut i = 0;
@@ -1291,11 +1291,11 @@ pub mod g1 {
 pub mod g2 {
    use super::super::{Bls12, Fq, Fq12, Fq2, FqRepr, Fr, FrRepr};
    use super::g1::G1Affine;
    use crate::{Engine, PairingCurveAffine};
    use ff::{BitIterator, Field, PrimeField, PrimeFieldRepr, SqrtField};
    use group::{CurveAffine, CurveProjective, EncodedPoint, GroupDecodingError};
    use rand_core::RngCore;
    use std::fmt;
    use {Engine, PairingCurveAffine};
    curve_impl!(
        "G2",
@@ -1325,7 +1325,7 @@ pub mod g2 {
    }
    impl fmt::Debug for G2Uncompressed {
-        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
            self.0[..].fmt(formatter)
        }
    }
@@ -1451,7 +1451,7 @@ pub mod g2 {
    }
    impl fmt::Debug for G2Compressed {
-        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
            self.0[..].fmt(formatter)
        }
    }
@@ -1640,7 +1640,7 @@ pub mod g2 {
    #[test]
    fn g2_generator() {
-        use SqrtField;
+        use crate::SqrtField;
        let mut x = Fq2::zero();
        let mut i = 0;
--- a/pairing/src/bls12_381/fq.rs
+++ b/pairing/src/bls12_381/fq.rs
@@ -2225,10 +2225,10 @@ fn test_fq_root_of_unity() {
 #[test]
 fn fq_field_tests() {
-    ::tests::field::random_field_tests::<Fq>();
+    crate::tests::field::random_field_tests::<Fq>();
-    ::tests::field::random_sqrt_tests::<Fq>();
+    crate::tests::field::random_sqrt_tests::<Fq>();
-    ::tests::field::random_frobenius_tests::<Fq, _>(Fq::char(), 13);
+    crate::tests::field::random_frobenius_tests::<Fq, _>(Fq::char(), 13);
-    ::tests::field::from_str_tests::<Fq>();
+    crate::tests::field::from_str_tests::<Fq>();
 }
 #[test]
@@ -2244,7 +2244,7 @@ fn test_fq_ordering() {
 #[test]
 fn fq_repr_tests() {
-    ::tests::repr::random_repr_tests::<Fq>();
+    crate::tests::repr::random_repr_tests::<Fq>();
 }
 #[test]
--- a/pairing/src/bls12_381/fq12.rs
+++ b/pairing/src/bls12_381/fq12.rs
@@ -12,7 +12,7 @@ pub struct Fq12 {
 }
 impl ::std::fmt::Display for Fq12 {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
        write!(f, "Fq12({} + {} * w)", self.c0, self.c1)
    }
 }
@@ -40,7 +40,7 @@ impl Fq12 {
 }
 impl Field for Fq12 {
-    fn random<R: RngCore>(rng: &mut R) -> Self {
+    fn random<R: RngCore + ?std::marker::Sized>(rng: &mut R) -> Self {
        Fq12 {
            c0: Fq6::random(rng),
            c1: Fq6::random(rng),
@@ -187,6 +187,6 @@ fn test_fq12_mul_by_014() {
 fn fq12_field_tests() {
    use ff::PrimeField;
-    ::tests::field::random_field_tests::<Fq12>();
+    crate::tests::field::random_field_tests::<Fq12>();
-    ::tests::field::random_frobenius_tests::<Fq12, _>(super::fq::Fq::char(), 13);
+    crate::tests::field::random_frobenius_tests::<Fq12, _>(super::fq::Fq::char(), 13);
 }
--- a/pairing/src/bls12_381/fq2.rs
+++ b/pairing/src/bls12_381/fq2.rs
@@ -12,7 +12,7 @@ pub struct Fq2 {
 }
 impl ::std::fmt::Display for Fq2 {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
        write!(f, "Fq2({} + {} * u)", self.c0, self.c1)
    }
 }
@@ -57,7 +57,7 @@ impl Fq2 {
 }
 impl Field for Fq2 {
-    fn random<R: RngCore>(rng: &mut R) -> Self {
+    fn random<R: RngCore + ?std::marker::Sized>(rng: &mut R) -> Self {
        Fq2 {
            c0: Fq::random(rng),
            c1: Fq::random(rng),
@@ -958,7 +958,7 @@ fn test_fq2_mul_nonresidue() {
 fn fq2_field_tests() {
    use ff::PrimeField;
-    ::tests::field::random_field_tests::<Fq2>();
+    crate::tests::field::random_field_tests::<Fq2>();
-    ::tests::field::random_sqrt_tests::<Fq2>();
+    crate::tests::field::random_sqrt_tests::<Fq2>();
-    ::tests::field::random_frobenius_tests::<Fq2, _>(super::fq::Fq::char(), 13);
+    crate::tests::field::random_frobenius_tests::<Fq2, _>(super::fq::Fq::char(), 13);
 }
--- a/pairing/src/bls12_381/fq6.rs
+++ b/pairing/src/bls12_381/fq6.rs
@@ -12,7 +12,7 @@ pub struct Fq6 {
 }
 impl ::std::fmt::Display for Fq6 {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
        write!(f, "Fq6({} + {} * v, {} * v^2)", self.c0, self.c1, self.c2)
    }
 }
@@ -100,7 +100,7 @@ impl Fq6 {
 }
 impl Field for Fq6 {
-    fn random<R: RngCore>(rng: &mut R) -> Self {
+    fn random<R: RngCore + ?std::marker::Sized>(rng: &mut R) -> Self {
        Fq6 {
            c0: Fq2::random(rng),
            c1: Fq2::random(rng),
@@ -378,6 +378,6 @@ fn test_fq6_mul_by_01() {
 fn fq6_field_tests() {
    use ff::PrimeField;
-    ::tests::field::random_field_tests::<Fq6>();
+    crate::tests::field::random_field_tests::<Fq6>();
-    ::tests::field::random_frobenius_tests::<Fq6, _>(super::fq::Fq::char(), 13);
+    crate::tests::field::random_frobenius_tests::<Fq6, _>(super::fq::Fq::char(), 13);
 }
--- a/pairing/src/bls12_381/fr.rs
+++ b/pairing/src/bls12_381/fr.rs
@@ -1015,13 +1015,13 @@ fn test_fr_root_of_unity() {
 #[test]
 fn fr_field_tests() {
-    ::tests::field::random_field_tests::<Fr>();
+    crate::tests::field::random_field_tests::<Fr>();
-    ::tests::field::random_sqrt_tests::<Fr>();
+    crate::tests::field::random_sqrt_tests::<Fr>();
-    ::tests::field::random_frobenius_tests::<Fr, _>(Fr::char(), 13);
+    crate::tests::field::random_frobenius_tests::<Fr, _>(Fr::char(), 13);
-    ::tests::field::from_str_tests::<Fr>();
+    crate::tests::field::from_str_tests::<Fr>();
 }
 #[test]
 fn fr_repr_tests() {
-    ::tests::repr::random_repr_tests::<Fr>();
+    crate::tests::repr::random_repr_tests::<Fr>();
 }
--- a/pairing/src/bls12_381/mod.rs
+++ b/pairing/src/bls12_381/mod.rs
@@ -1,3 +1,6 @@
 //! An implementation of the BLS12-381 pairing-friendly elliptic curve
 //! construction.
 mod ec;
 mod fq;
 mod fq12;
@@ -366,5 +369,5 @@ impl G2Prepared {
 #[test]
 fn bls12_engine_tests() {
-    ::tests::engine::engine_tests::<Bls12>();
+    crate::tests::engine::engine_tests::<Bls12>();
 }
--- a/pairing/src/bls12_381/tests/mod.rs
+++ b/pairing/src/bls12_381/tests/mod.rs
@@ -2,7 +2,7 @@ use ff::PrimeFieldRepr;
 use group::{CurveAffine, CurveProjective, EncodedPoint, GroupDecodingError};
 use super::*;
-use *;
+use crate::*;
 #[test]
 fn test_pairing_result_against_relic() {
--- a/pairing/src/lib.rs
+++ b/pairing/src/lib.rs
@@ -1,3 +1,5 @@
 //! A library for working with pairing-friendly curves.
 // `clippy` is a code linting tool for improving code quality by catching
 // common mistakes or strange code patterns. If the `cargo-clippy` feature
 // is provided, all compiler warnings are prohibited.
@@ -8,17 +10,11 @@
 #![cfg_attr(feature = "cargo-clippy", allow(clippy::many_single_char_names))]
 #![cfg_attr(feature = "cargo-clippy", allow(clippy::new_without_default))]
 #![cfg_attr(feature = "cargo-clippy", allow(clippy::write_literal))]
 // Catch documentation errors caused by code changes.
 #![deny(intra_doc_link_resolution_failure)]
 // Force public structures to implement Debug
 #![deny(missing_debug_implementations)]
 extern crate byteorder;
 extern crate ff;
 extern crate group;
 extern crate rand_core;
 #[cfg(test)]
 extern crate rand_xorshift;
 #[cfg(test)]
 pub mod tests;
@@ -87,7 +83,7 @@ pub trait Engine: ScalarEngine {
        >;
    /// Perform final exponentiation of the result of a miller loop.
-    fn final_exponentiation(&Self::Fqk) -> Option<Self::Fqk>;
+    fn final_exponentiation(_: &Self::Fqk) -> Option<Self::Fqk>;
    /// Performs a complete pairing operation `(p, q)`.
    fn pairing<G1, G2>(p: G1, q: G2) -> Self::Fqk
--- a/pairing/src/tests/engine.rs
+++ b/pairing/src/tests/engine.rs
@@ -2,7 +2,7 @@ use group::{CurveAffine, CurveProjective};
 use rand_core::SeedableRng;
 use rand_xorshift::XorShiftRng;
-use {Engine, Field, PairingCurveAffine, PrimeField};
+use crate::{Engine, Field, PairingCurveAffine, PrimeField};
 pub fn engine_tests<E: Engine>() {
    let mut rng = XorShiftRng::from_seed([
--- a/zcash_client_backend/Cargo.toml
+++ b/zcash_client_backend/Cargo.toml
@@ -1,25 +1,31 @@
 [package]
 name = "zcash_client_backend"
-version = "0.0.0"
+description = "APIs for creating shielded Zcash light clients"
 version = "0.1.0"
 authors = [
    "Jack Grigg <jack@z.cash>",
 ]
 homepage = "https://github.com/zcash/librustzcash"
 repository = "https://github.com/zcash/librustzcash"
 readme = "README.md"
 license = "MIT OR Apache-2.0"
 edition = "2018"
 [dependencies]
 bech32 = "0.7"
-bs58 = { version = "0.2", features = ["check"] }
+ff = { version = "0.5.0", path = "../ff" }
 ff = { path = "../ff" }
 hex = "0.3"
-pairing = { path = "../pairing" }
+pairing = { version = "0.15.0", path = "../pairing" }
 protobuf = "2"
 subtle = "2"
-zcash_primitives = { path = "../zcash_primitives" }
+zcash_primitives = { version = "0.1.0", path = "../zcash_primitives" }
 [build-dependencies]
 protobuf-codegen-pure = "2"
 [dev-dependencies]
 rand_core = "0.5"
 rand_os = "0.2"
 rand_xorshift = "0.2"
 [badges]
 maintenance = { status = "actively-developed" }
--- a/zcash_client_backend/README.md
+++ b/zcash_client_backend/README.md
@@ -1,12 +1,14 @@
 # zcash_client_backend
-This library contains Rust structs and traits for creating shielded Zcash light clients.
+This library contains Rust structs and traits for creating shielded Zcash light
 clients.
 ## License
 Licensed under either of
- * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
--- a/zcash_client_backend/src/constants.rs
+++ b/zcash_client_backend/src/constants.rs
@@ -1,9 +1,5 @@
 //! Zcash global and per-network constants.
 pub mod mainnet;
 pub mod testnet;
 pub mod regtest;
-
+pub mod testnet;
 pub const SPROUT_CONSENSUS_BRANCH_ID: u32 = 0;
 pub const OVERWINTER_CONSENSUS_BRANCH_ID: u32 = 0x5ba8_1b19;
 pub const SAPLING_CONSENSUS_BRANCH_ID: u32 = 0x76b8_09bb;
--- a/zcash_client_backend/src/constants/mainnet.rs
+++ b/zcash_client_backend/src/constants/mainnet.rs
@@ -1,7 +1,9 @@
 //! Constants for the Zcash main network.
 /// The mainnet coin type for ZEC, as defined by [SLIP 44].
 ///
 /// [SLIP 44]: https://github.com/satoshilabs/slips/blob/master/slip-0044.md
-pub const COIN_TYPE: u32 = 141;
+pub const COIN_TYPE: u32 = 133;
 /// The HRP for a Bech32-encoded mainnet [`ExtendedSpendingKey`].
 ///
@@ -23,16 +25,6 @@ pub const HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY: &str = "zxviews";
 ///
 /// Defined in section 5.6.4 of the [Zcash Protocol Specification].
 ///
-/// [`PaymentAddress`]: sapling_crypto::primitives::PaymentAddress
+/// [`PaymentAddress`]: zcash_primitives::primitives::PaymentAddress
 /// [Zcash Protocol Specification]: https://github.com/zcash/zips/blob/master/protocol/protocol.pdf
 pub const HRP_SAPLING_PAYMENT_ADDRESS: &str = "zs";
 /// The prefix for a Base58Check-encoded mainnet [`TransparentAddress::PublicKey`].
 ///
 /// [`TransparentAddress::PublicKey`]: zcash_primitives::legacy::TransparentAddress::PublicKey
 pub const B58_PUBKEY_ADDRESS_PREFIX: [u8; 1] = [0x3c];
 /// The prefix for a Base58Check-encoded mainnet [`TransparentAddress::Script`].
 ///
 /// [`TransparentAddress::Script`]: zcash_primitives::legacy::TransparentAddress::Script
 pub const B58_SCRIPT_ADDRESS_PREFIX: [u8; 1] = [0x55];
--- a/zcash_client_backend/src/constants/regtest.rs
+++ b/zcash_client_backend/src/constants/regtest.rs
@@ -1,38 +1,45 @@
-/// The testnet coin type for ZEC, as defined by [SLIP 44].
+//! # Regtest constants
-///
+//!
-/// [SLIP 44]: https://github.com/satoshilabs/slips/blob/master/slip-0044.md
+//! `regtest` is a `zcashd`-specific environment used for local testing. They mostly reuse
 //! the testnet constants.
 //! These constants are defined in [the `zcashd` codebase].
 //! [the `zcashd` codebase]: https://github.com/zcash/zcash/blob/128d863fb8be39ee294fda397c1ce3ba3b889cb2/src/chainparams.cpp#L482-L496
 /// The regtest cointype reuses the testnet cointype
 pub const COIN_TYPE: u32 = 1;
-/// The HRP for a Bech32-encoded testnet [`ExtendedSpendingKey`].
+/// The HRP for a Bech32-encoded regtest [`ExtendedSpendingKey`].
 ///
-/// Defined in [ZIP 32].
+/// It is defined in [the `zcashd` codebase].
 ///
 /// [`ExtendedSpendingKey`]: zcash_primitives::zip32::ExtendedSpendingKey
-/// [ZIP 32]: https://github.com/zcash/zips/blob/master/zip-0032.rst
+/// [the `zcashd` codebase]: https://github.com/zcash/zcash/blob/128d863fb8be39ee294fda397c1ce3ba3b889cb2/src/chainparams.cpp#L496
 pub const HRP_SAPLING_EXTENDED_SPENDING_KEY: &str = "secret-extended-key-regtest";
-/// The HRP for a Bech32-encoded testnet [`ExtendedFullViewingKey`].
+/// The HRP for a Bech32-encoded regtest [`ExtendedFullViewingKey`].
 ///
-/// Defined in [ZIP 32].
+/// It is defined in [the `zcashd` codebase].
 ///
 /// [`ExtendedFullViewingKey`]: zcash_primitives::zip32::ExtendedFullViewingKey
-/// [ZIP 32]: https://github.com/zcash/zips/blob/master/zip-0032.rst
+/// [the `zcashd` codebase]: https://github.com/zcash/zcash/blob/128d863fb8be39ee294fda397c1ce3ba3b889cb2/src/chainparams.cpp#L494
 pub const HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY: &str = "zxviewregtestsapling";
-/// The HRP for a Bech32-encoded testnet [`PaymentAddress`].
+/// The HRP for a Bech32-encoded regtest [`PaymentAddress`].
 ///
-/// Defined in section 5.6.4 of the [Zcash Protocol Specification].
+/// It is defined in [the `zcashd` codebase].
 ///
-/// [`PaymentAddress`]: sapling_crypto::primitives::PaymentAddress
+/// [`PaymentAddress`]: zcash_primitives::primitives::PaymentAddress
-/// [Zcash Protocol Specification]: https://github.com/zcash/zips/blob/master/protocol/protocol.pdf
+/// [the `zcashd` codebase]: https://github.com/zcash/zcash/blob/128d863fb8be39ee294fda397c1ce3ba3b889cb2/src/chainparams.cpp#L493
 pub const HRP_SAPLING_PAYMENT_ADDRESS: &str = "zregtestsapling";
-/// The prefix for a Base58Check-encoded testnet [`TransparentAddress::PublicKey`].
+/// The prefix for a Base58Check-encoded regtest [`TransparentAddress::PublicKey`].
 /// Same as the testnet prefix.
 ///
 /// [`TransparentAddress::PublicKey`]: zcash_primitives::legacy::TransparentAddress::PublicKey
 pub const B58_PUBKEY_ADDRESS_PREFIX: [u8; 2] = [0x1d, 0x25];
-/// The prefix for a Base58Check-encoded testnet [`TransparentAddress::Script`].
+/// The prefix for a Base58Check-encoded regtest [`TransparentAddress::Script`].
 /// Same as the testnet prefix.
 ///
 /// [`TransparentAddress::Script`]: zcash_primitives::legacy::TransparentAddress::Script
 pub const B58_SCRIPT_ADDRESS_PREFIX: [u8; 2] = [0x1c, 0xba];
--- a/zcash_client_backend/src/constants/testnet.rs
+++ b/zcash_client_backend/src/constants/testnet.rs
@@ -1,3 +1,5 @@
 //! Constants for the Zcash test network.
 /// The testnet coin type for ZEC, as defined by [SLIP 44].
 ///
 /// [SLIP 44]: https://github.com/satoshilabs/slips/blob/master/slip-0044.md
@@ -23,16 +25,6 @@ pub const HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY: &str = "zxviewtestsapling";
 ///
 /// Defined in section 5.6.4 of the [Zcash Protocol Specification].
 ///
-/// [`PaymentAddress`]: sapling_crypto::primitives::PaymentAddress
+/// [`PaymentAddress`]: zcash_primitives::primitives::PaymentAddress
 /// [Zcash Protocol Specification]: https://github.com/zcash/zips/blob/master/protocol/protocol.pdf
 pub const HRP_SAPLING_PAYMENT_ADDRESS: &str = "ztestsapling";
 /// The prefix for a Base58Check-encoded testnet [`TransparentAddress::PublicKey`].
 ///
 /// [`TransparentAddress::PublicKey`]: zcash_primitives::legacy::TransparentAddress::PublicKey
 pub const B58_PUBKEY_ADDRESS_PREFIX: [u8; 2] = [0x1d, 0x25];
 /// The prefix for a Base58Check-encoded testnet [`TransparentAddress::Script`].
 ///
 /// [`TransparentAddress::Script`]: zcash_primitives::legacy::TransparentAddress::Script
 pub const B58_SCRIPT_ADDRESS_PREFIX: [u8; 2] = [0x1c, 0xba];
--- a/zcash_client_backend/src/decrypt.rs
+++ b/zcash_client_backend/src/decrypt.rs
@@ -0,0 +1,76 @@
 use pairing::bls12_381::Bls12;
 use zcash_primitives::{
    note_encryption::{try_sapling_note_decryption, try_sapling_output_recovery, Memo},
    primitives::{Note, PaymentAddress},
    transaction::Transaction,
    zip32::ExtendedFullViewingKey,
    JUBJUB,
 };
 /// A decrypted shielded output.
 pub struct DecryptedOutput {
    /// The index of the output within [`shielded_outputs`].
    ///
    /// [`shielded_outputs`]: zcash_primitives::transaction::TransactionData
    pub index: usize,
    /// The note within the output.
    pub note: Note<Bls12>,
    /// The address the note was sent to.
    pub to: PaymentAddress<Bls12>,
    /// The memo included with the note.
    pub memo: Memo,
    /// True if this output was recovered using an [`OutgoingViewingKey`], meaning that
    /// this is a logical output of the transaction.
    ///
    /// [`OutgoingViewingKey`]: zcash_primitives::keys::OutgoingViewingKey
    pub outgoing: bool,
 }
 /// Scans a [`Transaction`] for any information that can be decrypted by the set of
 /// [`ExtendedFullViewingKey`]s.
 pub fn decrypt_transaction(
    tx: &Transaction,
    extfvks: &[ExtendedFullViewingKey],
 ) -> Vec<DecryptedOutput> {
    let mut decrypted = vec![];
    // Cache IncomingViewingKey calculation
    let vks: Vec<_> = extfvks
        .iter()
        .map(|extfvk| (extfvk.fvk.vk.ivk(), extfvk.fvk.ovk))
        .collect();
    for (index, output) in tx.shielded_outputs.iter().enumerate() {
        let epk = match output.ephemeral_key.as_prime_order(&JUBJUB) {
            Some(p) => p,
            None => continue,
        };
        for (ivk, ovk) in &vks {
            let ((note, to, memo), outgoing) =
                match try_sapling_note_decryption(ivk, &epk, &output.cmu, &output.enc_ciphertext) {
                    Some(ret) => (ret, false),
                    None => match try_sapling_output_recovery(
                        ovk,
                        &output.cv,
                        &output.cmu,
                        &epk,
                        &output.enc_ciphertext,
                        &output.out_ciphertext,
                    ) {
                        Some(ret) => (ret, true),
                        None => continue,
                    },
                };
            decrypted.push(DecryptedOutput {
                index,
                note,
                to,
                memo,
                outgoing,
            })
        }
    }
    decrypted
 }
--- a/zcash_client_backend/src/encoding.rs
+++ b/zcash_client_backend/src/encoding.rs
@@ -2,17 +2,14 @@
 //!
 //! Human-Readable Prefixes (HRPs) for Bech32 encodings are located in the [`constants`]
 //! module.
 //!
 //! [`constants`]: crate::constants
 use bech32::{self, Error, FromBase32, ToBase32};
 use bs58::{self, decode::DecodeError};
 use pairing::bls12_381::Bls12;
 use std::io::{self, Write};
 use zcash_primitives::{
-    jubjub::edwards,
+    primitives::PaymentAddress,
    primitives::{Diversifier, PaymentAddress},
 };
 use zcash_primitives::{
    legacy::TransparentAddress,
    zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    JUBJUB,
 };
@@ -115,10 +112,11 @@ pub fn decode_extended_full_viewing_key(
 ///     0xbc, 0xe5,
 /// ]);
 ///
-/// let pa = PaymentAddress {
+/// let pa = PaymentAddress::from_parts(
-///     diversifier: Diversifier([0u8; 11]),
+///     Diversifier([0u8; 11]),
-///     pk_d: edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
+///     edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
-/// };
+/// )
 /// .unwrap();
 ///
 /// assert_eq!(
 ///     encode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, &pa),
@@ -126,10 +124,7 @@ pub fn decode_extended_full_viewing_key(
 /// );
 /// ```
 pub fn encode_payment_address(hrp: &str, addr: &PaymentAddress<Bls12>) -> String {
-    bech32_encode(hrp, |w| {
+    bech32_encode(hrp, |w| w.write_all(&addr.to_bytes()))
        w.write_all(&addr.diversifier.0)?;
        addr.pk_d.write(w)
    })
 }
 /// Decodes a [`PaymentAddress`] from a Bech32-encoded string.
@@ -155,10 +150,11 @@ pub fn encode_payment_address(hrp: &str, addr: &PaymentAddress<Bls12>) -> String
 ///     0xbc, 0xe5,
 /// ]);
 ///
-/// let pa = PaymentAddress {
+/// let pa = PaymentAddress::from_parts(
-///     diversifier: Diversifier([0u8; 11]),
+///     Diversifier([0u8; 11]),
-///     pk_d: edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
+///     edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
-/// };
+/// )
 /// .unwrap();
 ///
 /// assert_eq!(
 ///     decode_payment_address(
@@ -170,127 +166,16 @@ pub fn encode_payment_address(hrp: &str, addr: &PaymentAddress<Bls12>) -> String
 /// ```
 pub fn decode_payment_address(hrp: &str, s: &str) -> Result<Option<PaymentAddress<Bls12>>, Error> {
    bech32_decode(hrp, s, |data| {
-        let mut diversifier = Diversifier([0; 11]);
+        if data.len() != 43 {
        diversifier.0.copy_from_slice(&data[0..11]);
        // Check that the diversifier is valid
        if diversifier.g_d::<Bls12>(&JUBJUB).is_none() {
            return None;
        }
-        edwards::Point::<Bls12, _>::read(&data[11..], &JUBJUB)
+        let mut bytes = [0; 43];
-            .ok()?
+        bytes.copy_from_slice(&data);
-            .as_prime_order(&JUBJUB)
+        PaymentAddress::<Bls12>::from_bytes(&bytes, &JUBJUB)
            .map(|pk_d| PaymentAddress { pk_d, diversifier })
    })
 }
 /// Writes a [`TransparentAddress`] as a Base58Check-encoded string.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_backend::{
 ///     constants::testnet::{B58_PUBKEY_ADDRESS_PREFIX, B58_SCRIPT_ADDRESS_PREFIX},
 ///     encoding::encode_transparent_address,
 /// };
 /// use zcash_primitives::legacy::TransparentAddress;
 ///
 /// assert_eq!(
 ///     encode_transparent_address(
 ///         &B58_PUBKEY_ADDRESS_PREFIX,
 ///         &B58_SCRIPT_ADDRESS_PREFIX,
 ///         &TransparentAddress::PublicKey([0; 20]),
 ///     ),
 ///     "tm9iMLAuYMzJ6jtFLcA7rzUmfreGuKvr7Ma",
 /// );
 ///
 /// assert_eq!(
 ///     encode_transparent_address(
 ///         &B58_PUBKEY_ADDRESS_PREFIX,
 ///         &B58_SCRIPT_ADDRESS_PREFIX,
 ///         &TransparentAddress::Script([0; 20]),
 ///     ),
 ///     "t26YoyZ1iPgiMEWL4zGUm74eVWfhyDMXzY2",
 /// );
 /// ```
 pub fn encode_transparent_address(
    pubkey_version: &[u8],
    script_version: &[u8],
    addr: &TransparentAddress,
 ) -> String {
    let decoded = match addr {
        TransparentAddress::PublicKey(key_id) => {
            let mut decoded = vec![0; pubkey_version.len() + 20];
            decoded[..pubkey_version.len()].copy_from_slice(pubkey_version);
            decoded[pubkey_version.len()..].copy_from_slice(key_id);
            decoded
        }
        TransparentAddress::Script(script_id) => {
            let mut decoded = vec![0; script_version.len() + 20];
            decoded[..script_version.len()].copy_from_slice(script_version);
            decoded[script_version.len()..].copy_from_slice(script_id);
            decoded
        }
    };
    bs58::encode(decoded).with_check().into_string()
 }
 /// Decodes a [`TransparentAddress`] from a Base58Check-encoded string.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_backend::{
 ///     constants::testnet::{B58_PUBKEY_ADDRESS_PREFIX, B58_SCRIPT_ADDRESS_PREFIX},
 ///     encoding::decode_transparent_address,
 /// };
 /// use zcash_primitives::legacy::TransparentAddress;
 ///
 /// assert_eq!(
 ///     decode_transparent_address(
 ///         &B58_PUBKEY_ADDRESS_PREFIX,
 ///         &B58_SCRIPT_ADDRESS_PREFIX,
 ///         "tm9iMLAuYMzJ6jtFLcA7rzUmfreGuKvr7Ma",
 ///     ),
 ///     Ok(Some(TransparentAddress::PublicKey([0; 20]))),
 /// );
 ///
 /// assert_eq!(
 ///     decode_transparent_address(
 ///         &B58_PUBKEY_ADDRESS_PREFIX,
 ///         &B58_SCRIPT_ADDRESS_PREFIX,
 ///         "t26YoyZ1iPgiMEWL4zGUm74eVWfhyDMXzY2",
 ///     ),
 ///     Ok(Some(TransparentAddress::Script([0; 20]))),
 /// );
 /// ```
 pub fn decode_transparent_address(
    pubkey_version: &[u8],
    script_version: &[u8],
    s: &str,
 ) -> Result<Option<TransparentAddress>, DecodeError> {
    let decoded = bs58::decode(s).with_check(None).into_vec()?;
    if &decoded[..pubkey_version.len()] == pubkey_version {
        if decoded.len() == pubkey_version.len() + 20 {
            let mut data = [0; 20];
            data.copy_from_slice(&decoded[pubkey_version.len()..]);
            Ok(Some(TransparentAddress::PublicKey(data)))
        } else {
            Ok(None)
        }
    } else if &decoded[..script_version.len()] == script_version {
        if decoded.len() == script_version.len() + 20 {
            let mut data = [0; 20];
            data.copy_from_slice(&decoded[script_version.len()..]);
            Ok(Some(TransparentAddress::Script(data)))
        } else {
            Ok(None)
        }
    } else {
        Ok(None)
    }
 }
 #[cfg(test)]
 mod tests {
    use pairing::bls12_381::Bls12;
@@ -300,11 +185,95 @@ mod tests {
    use zcash_primitives::{
        jubjub::edwards,
        primitives::{Diversifier, PaymentAddress},
        zip32::ExtendedSpendingKey,
    };
-    use super::{decode_payment_address, encode_payment_address};
+    use super::{
        decode_extended_full_viewing_key, decode_extended_spending_key, decode_payment_address,
        encode_extended_full_viewing_key, encode_extended_spending_key, encode_payment_address,
    };
    use crate::constants;
    #[test]
    fn extended_spending_key() {
        let extsk = ExtendedSpendingKey::master(&[0; 32][..]);
        let encoded_main = "secret-extended-key-main1qqqqqqqqqqqqqq8n3zjjmvhhr854uy3qhpda3ml34haf0x388z5r7h4st4kpsf6qysqws3xh6qmha7gna72fs2n4clnc9zgyd22s658f65pex4exe56qjk5pqj9vfdq7dfdhjc2rs9jdwq0zl99uwycyrxzp86705rk687spn44e2uhm7h0hsagfvkk4n7n6nfer6u57v9cac84t7nl2zth0xpyfeg0w2p2wv2yn6jn923aaz0vdaml07l60ahapk6efchyxwysrvjs87qvlj";
        let encoded_test = "secret-extended-key-test1qqqqqqqqqqqqqq8n3zjjmvhhr854uy3qhpda3ml34haf0x388z5r7h4st4kpsf6qysqws3xh6qmha7gna72fs2n4clnc9zgyd22s658f65pex4exe56qjk5pqj9vfdq7dfdhjc2rs9jdwq0zl99uwycyrxzp86705rk687spn44e2uhm7h0hsagfvkk4n7n6nfer6u57v9cac84t7nl2zth0xpyfeg0w2p2wv2yn6jn923aaz0vdaml07l60ahapk6efchyxwysrvjsvzyw8j";
        assert_eq!(
            encode_extended_spending_key(
                constants::mainnet::HRP_SAPLING_EXTENDED_SPENDING_KEY,
                &extsk
            ),
            encoded_main
        );
        assert_eq!(
            decode_extended_spending_key(
                constants::mainnet::HRP_SAPLING_EXTENDED_SPENDING_KEY,
                encoded_main
            )
            .unwrap(),
            Some(extsk.clone())
        );
        assert_eq!(
            encode_extended_spending_key(
                constants::testnet::HRP_SAPLING_EXTENDED_SPENDING_KEY,
                &extsk
            ),
            encoded_test
        );
        assert_eq!(
            decode_extended_spending_key(
                constants::testnet::HRP_SAPLING_EXTENDED_SPENDING_KEY,
                encoded_test
            )
            .unwrap(),
            Some(extsk)
        );
    }
    #[test]
    fn extended_full_viewing_key() {
        let extfvk = (&ExtendedSpendingKey::master(&[0; 32][..])).into();
        let encoded_main = "zxviews1qqqqqqqqqqqqqq8n3zjjmvhhr854uy3qhpda3ml34haf0x388z5r7h4st4kpsf6qy3zw4wc246aw9rlfyg5ndlwvne7mwdq0qe6vxl42pqmcf8pvmmd5slmjxduqa9evgej6wa3th2505xq4nggrxdm93rxk4rpdjt5nmq2vn44e2uhm7h0hsagfvkk4n7n6nfer6u57v9cac84t7nl2zth0xpyfeg0w2p2wv2yn6jn923aaz0vdaml07l60ahapk6efchyxwysrvjsxmansf";
        let encoded_test = "zxviewtestsapling1qqqqqqqqqqqqqq8n3zjjmvhhr854uy3qhpda3ml34haf0x388z5r7h4st4kpsf6qy3zw4wc246aw9rlfyg5ndlwvne7mwdq0qe6vxl42pqmcf8pvmmd5slmjxduqa9evgej6wa3th2505xq4nggrxdm93rxk4rpdjt5nmq2vn44e2uhm7h0hsagfvkk4n7n6nfer6u57v9cac84t7nl2zth0xpyfeg0w2p2wv2yn6jn923aaz0vdaml07l60ahapk6efchyxwysrvjs8evfkz";
        assert_eq!(
            encode_extended_full_viewing_key(
                constants::mainnet::HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
                &extfvk
            ),
            encoded_main
        );
        assert_eq!(
            decode_extended_full_viewing_key(
                constants::mainnet::HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
                encoded_main
            )
            .unwrap(),
            Some(extfvk.clone())
        );
        assert_eq!(
            encode_extended_full_viewing_key(
                constants::testnet::HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
                &extfvk
            ),
            encoded_test
        );
        assert_eq!(
            decode_extended_full_viewing_key(
                constants::testnet::HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
                encoded_test
            )
            .unwrap(),
            Some(extfvk)
        );
    }
    #[test]
    fn payment_address() {
        let rng = &mut XorShiftRng::from_seed([
@@ -312,10 +281,11 @@ mod tests {
            0xbc, 0xe5,
        ]);
-        let addr = PaymentAddress {
+        let addr = PaymentAddress::from_parts(
-            diversifier: Diversifier([0u8; 11]),
+            Diversifier([0u8; 11]),
-            pk_d: edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
+            edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
-        };
+        )
        .unwrap();
        let encoded_main =
            "zs1qqqqqqqqqqqqqqqqqrjq05nyfku05msvu49mawhg6kr0wwljahypwyk2h88z6975u563j8nfaxd";
@@ -356,10 +326,11 @@ mod tests {
            0xbc, 0xe5,
        ]);
-        let addr = PaymentAddress {
+        let addr = PaymentAddress::from_parts(
-            diversifier: Diversifier([1u8; 11]),
+            Diversifier([1u8; 11]),
-            pk_d: edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
+            edwards::Point::<Bls12, _>::rand(rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
-        };
+        )
        .unwrap();
        let encoded_main =
            encode_payment_address(constants::mainnet::HRP_SAPLING_PAYMENT_ADDRESS, &addr);
--- a/zcash_client_backend/src/keys.rs
+++ b/zcash_client_backend/src/keys.rs
@@ -5,6 +5,10 @@ use zcash_primitives::zip32::{ChildIndex, ExtendedSpendingKey};
 /// Derives the ZIP 32 [`ExtendedSpendingKey`] for a given coin type and account from the
 /// given seed.
 ///
 /// # Panics
 ///
 /// Panics if `seed` is shorter than 32 bytes.
 ///
 /// # Examples
 ///
 /// ```
@@ -13,6 +17,10 @@ use zcash_primitives::zip32::{ChildIndex, ExtendedSpendingKey};
 /// let extsk = spending_key(&[0; 32][..], COIN_TYPE, 0);
 /// ```
 pub fn spending_key(seed: &[u8], coin_type: u32, account: u32) -> ExtendedSpendingKey {
    if seed.len() < 32 {
        panic!("ZIP 32 seeds MUST be at least 32 bytes");
    }
    ExtendedSpendingKey::from_path(
        &ExtendedSpendingKey::master(&seed),
        &[
@@ -22,3 +30,14 @@ pub fn spending_key(seed: &[u8], coin_type: u32, account: u32) -> ExtendedSpendi
        ],
    )
 }
 #[cfg(test)]
 mod tests {
    use super::spending_key;
    #[test]
    #[should_panic]
    fn spending_key_panics_on_short_seed() {
        let _ = spending_key(&[0; 31][..], 0, 0);
    }
 }
--- a/zcash_client_backend/src/lib.rs
+++ b/zcash_client_backend/src/lib.rs
@@ -3,9 +3,15 @@
 //! `zcash_client_backend` contains Rust structs and traits for creating shielded Zcash
 //! light clients.
 // Catch documentation errors caused by code changes.
 #![deny(intra_doc_link_resolution_failure)]
 pub mod constants;
 mod decrypt;
 pub mod encoding;
 pub mod keys;
 pub mod proto;
 pub mod wallet;
 pub mod welding_rig;
 pub use decrypt::{decrypt_transaction, DecryptedOutput};
--- a/zcash_client_backend/src/welding_rig.rs
+++ b/zcash_client_backend/src/welding_rig.rs
@@ -134,12 +134,11 @@ pub fn scan_block(
            // mutable references to wtxs for too long.
            let mut block_witnesses: Vec<_> = wtxs
                .iter_mut()
-                .map(|tx| {
+                .flat_map(|tx| {
                    tx.shielded_outputs
                        .iter_mut()
                        .map(|output| &mut output.witness)
                })
                .flatten()
                .collect();
            for to_scan in tx.outputs.into_iter().enumerate() {
@@ -186,8 +185,7 @@ pub fn scan_block(
 mod tests {
    use ff::{Field, PrimeField, PrimeFieldRepr};
    use pairing::bls12_381::{Bls12, Fr};
-    use rand_core::RngCore;
+    use rand_core::{OsRng, RngCore};
    use rand_os::OsRng;
    use zcash_primitives::{
        jubjub::{fs::Fs, FixedGenerators, JubjubParams, ToUniform},
        merkle_tree::CommitmentTree,
@@ -254,8 +252,8 @@ mod tests {
        // Create a fake Note for the account
        let mut rng = OsRng;
        let note = Note {
-            g_d: to.diversifier.g_d::<Bls12>(&JUBJUB).unwrap(),
+            g_d: to.diversifier().g_d::<Bls12>(&JUBJUB).unwrap(),
-            pk_d: to.pk_d.clone(),
+            pk_d: to.pk_d().clone(),
            value: value.into(),
            r: Fs::random(&mut rng),
        };
--- a/zcash_client_sqlite/Cargo.toml
+++ b/zcash_client_sqlite/Cargo.toml
@@ -1,27 +0,0 @@
 [package]
 name = "zcash_client_sqlite"
 version = "0.0.0"
 authors = [
    "Jack Grigg <jack@z.cash>",
 ]
 edition = "2018"
 [dependencies]
 bech32 = "0.7"
 bs58 = { version = "0.2", features = ["check"] }
 ff = { path = "../ff" }
 pairing = { path = "../pairing" }
 protobuf = "2"
 rusqlite = { version = "0.20", features = ["bundled"] }
 time = "0.1"
 zcash_client_backend = { path = "../zcash_client_backend" }
 zcash_primitives = { path = "../zcash_primitives" }
 [dev-dependencies]
 rand_core = "0.5"
 rand_os = "0.2"
 tempfile = "3"
 zcash_proofs = { path = "../zcash_proofs" }
 [features]
 mainnet = []
--- a/zcash_client_sqlite/README.md
+++ b/zcash_client_sqlite/README.md
@@ -1,60 +0,0 @@
 # Security Disclaimer
 #### :warning:  WARNING: This is an *early preview*
 ----
 In the spirit of transparency, we provide this as a window into what we are actively
 developing. This is an alpha build, not yet intended for 3rd party use. Please be advised
 of the following:
 * 🛑 This code currently is not audited. 🛑
 * ❌ This is a public, active branch with **no support**.
 * ❌ The code **does not have** documentation that is reviewed and approved by our Documentation team.
 * ❌ The code **does not have** adequate unit tests, acceptance tests and stress tests.
 * ❌ The code **does not have** automated tests that use the officially supported CI system.
 * ❌ The code **has not been subjected to thorough review** by engineers at the Electric Coin Company.
 * :warning: This library **is** compatible with the latest version of zcashd, but there **is no** automated testing of this.
 * :heavy_check_mark: The library **is not** majorly broken in some way.
 * :heavy_check_mark: The library **does run** on mainnet and testnet.
 * ❌ We **are actively rebasing** this branch and adding features where/when needed.
 * ❌ We **do not** undertake appropriate security coverage (threat models, review, response, etc.).
 * :heavy_check_mark: There is a product manager for this library.
 * :heavy_check_mark: Electric Coin Company maintains the library as we discover bugs and do network upgrades/minor releases.
 * :heavy_check_mark: Users can expect to get a response within a few weeks after submitting an issue.
 * ❌ The User Support team **has not yet been briefed** on the features provided to users and the functionality of the associated test-framework.
 * ❌ The code is **not fully-documented**.
 ### 🛑 Use of this code may lead to a loss of funds 🛑
 Use of this code in its current form or with modifications may lead to loss of funds, loss
 of "expected" privacy, or denial of service for a large portion of users, or a bug which
 could leverage any of those kinds of attacks (especially a "0 day" where we suspect few
 people know about the vulnerability).
 ### :eyes: At this time, this is for preview purposes only. :eyes:
 ----
 # zcash_client_sqlite
 This library contains APIs that collectively implement a Zcash light client in
 an SQLite database.
 ## License
 Licensed under either of
 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 at your option.
 ### Contribution
 Unless you explicitly state otherwise, any contribution intentionally
 submitted for inclusion in the work by you, as defined in the Apache-2.0
 license, shall be dual licensed as above, without any additional terms or
 conditions.
--- a/zcash_client_sqlite/src/address.rs
+++ b/zcash_client_sqlite/src/address.rs
@@ -1,63 +0,0 @@
 //! Structs for handling supported address types.
 use pairing::bls12_381::Bls12;
 use zcash_client_backend::encoding::{
    decode_payment_address, decode_transparent_address, encode_payment_address,
    encode_transparent_address,
 };
 use zcash_primitives::{legacy::TransparentAddress, primitives::PaymentAddress};
 #[cfg(feature = "mainnet")]
 use zcash_client_backend::constants::mainnet::{
    B58_PUBKEY_ADDRESS_PREFIX, B58_SCRIPT_ADDRESS_PREFIX, HRP_SAPLING_PAYMENT_ADDRESS,
 };
 #[cfg(not(feature = "mainnet"))]
 use zcash_client_backend::constants::testnet::{
    B58_PUBKEY_ADDRESS_PREFIX, B58_SCRIPT_ADDRESS_PREFIX, HRP_SAPLING_PAYMENT_ADDRESS,
 };
 /// An address that funds can be sent to.
 pub enum RecipientAddress {
    Shielded(PaymentAddress<Bls12>),
    Transparent(TransparentAddress),
 }
 impl From<PaymentAddress<Bls12>> for RecipientAddress {
    fn from(addr: PaymentAddress<Bls12>) -> Self {
        RecipientAddress::Shielded(addr)
    }
 }
 impl From<TransparentAddress> for RecipientAddress {
    fn from(addr: TransparentAddress) -> Self {
        RecipientAddress::Transparent(addr)
    }
 }
 impl RecipientAddress {
    pub fn from_str(s: &str) -> Option<Self> {
        if let Ok(Some(pa)) = decode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, s) {
            Some(pa.into())
        } else if let Ok(Some(addr)) =
            decode_transparent_address(&B58_PUBKEY_ADDRESS_PREFIX, &B58_SCRIPT_ADDRESS_PREFIX, s)
        {
            Some(addr.into())
        } else {
            None
        }
    }
    pub fn to_string(&self) -> String {
        match self {
            RecipientAddress::Shielded(pa) => {
                encode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, pa)
            }
            RecipientAddress::Transparent(addr) => encode_transparent_address(
                &B58_PUBKEY_ADDRESS_PREFIX,
                &B58_SCRIPT_ADDRESS_PREFIX,
                addr,
            ),
        }
    }
 }
--- a/zcash_client_sqlite/src/chain.rs
+++ b/zcash_client_sqlite/src/chain.rs
@@ -1,469 +0,0 @@
 //! Functions for enforcing chain validity and handling chain reorgs.
 //!
 //! # Examples
 //!
 //! ```
 //! use zcash_client_sqlite::{
 //!     chain::{rewind_to_height, validate_combined_chain},
 //!     error::ErrorKind,
 //!     scan::scan_cached_blocks,
 //! };
 //!
 //! let db_cache = "/path/to/cache.db";
 //! let db_data = "/path/to/data.db";
 //!
 //! // 1) Download new CompactBlocks into db_cache.
 //!
 //! // 2) Run the chain validator on the received blocks.
 //! //
 //! // Given that we assume the server always gives us correct-at-the-time blocks, any
 //! // errors are in the blocks we have previously cached or scanned.
 //! if let Err(e) = validate_combined_chain(&db_cache, &db_data) {
 //!     match e.kind() {
 //!         ErrorKind::InvalidChain(upper_bound, _) => {
 //!             // a) Pick a height to rewind to.
 //!             //
 //!             // This might be informed by some external chain reorg information, or
 //!             // heuristics such as the platform, available bandwidth, size of recent
 //!             // CompactBlocks, etc.
 //!             let rewind_height = upper_bound - 10;
 //!
 //!             // b) Rewind scanned block information.
 //!             rewind_to_height(&db_data, rewind_height);
 //!
 //!             // c) Delete cached blocks from rewind_height onwards.
 //!             //
 //!             // This does imply that assumed-valid blocks will be re-downloaded, but it
 //!             // is also possible that in the intervening time, a chain reorg has
 //!             // occurred that orphaned some of those blocks.
 //!
 //!             // d) If there is some separate thread or service downloading
 //!             // CompactBlocks, tell it to go back and download from rewind_height
 //!             // onwards.
 //!         }
 //!         _ => {
 //!             // Handle other errors.
 //!         }
 //!     }
 //! }
 //!
 //! // 3) Scan (any remaining) cached blocks.
 //! //
 //! // At this point, the cache and scanned data are locally consistent (though not
 //! // necessarily consistent with the latest chain tip - this would be discovered the
 //! // next time this codepath is executed after new blocks are received).
 //! scan_cached_blocks(&db_cache, &db_data);
 //! ```
 use protobuf::parse_from_bytes;
 use rusqlite::{Connection, NO_PARAMS};
 use std::path::Path;
 use zcash_client_backend::proto::compact_formats::CompactBlock;
 use crate::{
    error::{Error, ErrorKind},
    SAPLING_ACTIVATION_HEIGHT,
 };
 #[derive(Debug)]
 pub enum ChainInvalidCause {
    PrevHashMismatch,
 }
 struct CompactBlockRow {
    height: i32,
    data: Vec<u8>,
 }
 /// Checks that the scanned blocks in the data database, when combined with the recent
 /// `CompactBlock`s in the cache database, form a valid chain.
 ///
 /// This function is built on the core assumption that the information provided in the
 /// cache database is more likely to be accurate than the previously-scanned information.
 /// This follows from the design (and trust) assumption that the `lightwalletd` server
 /// provides accurate block information as of the time it was requested.
 ///
 /// Returns:
 /// - `Ok(())` if the combined chain is valid.
 /// - `Err(ErrorKind::InvalidChain(upper_bound, cause))` if the combined chain is invalid.
 ///   `upper_bound` is the height of the highest invalid block (on the assumption that the
 ///   highest block in the cache database is correct).
 /// - `Err(e)` if there was an error during validation unrelated to chain validity.
 ///
 /// This function does not mutate either of the databases.
 pub fn validate_combined_chain<P: AsRef<Path>, Q: AsRef<Path>>(
    db_cache: P,
    db_data: Q,
 ) -> Result<(), Error> {
    let cache = Connection::open(db_cache)?;
    let data = Connection::open(db_data)?;
    // Recall where we synced up to previously.
    // If we have never synced, use Sapling activation height to select all cached CompactBlocks.
    let (have_scanned, last_scanned_height) =
        data.query_row("SELECT MAX(height) FROM blocks", NO_PARAMS, |row| {
            row.get(0)
                .map(|h| (true, h))
                .or(Ok((false, SAPLING_ACTIVATION_HEIGHT - 1)))
        })?;
    // Fetch the CompactBlocks we need to validate
    let mut stmt_blocks = cache
        .prepare("SELECT height, data FROM compactblocks WHERE height > ? ORDER BY height DESC")?;
    let mut rows = stmt_blocks.query_map(&[last_scanned_height], |row| {
        Ok(CompactBlockRow {
            height: row.get(0)?,
            data: row.get(1)?,
        })
    })?;
    // Take the highest cached block as accurate.
    let (mut last_height, mut last_prev_hash) = {
        let assumed_correct = match rows.next() {
            Some(row) => row?,
            None => {
                // No cached blocks, and we've already validated the blocks we've scanned,
                // so there's nothing to validate.
                // TODO: Maybe we still want to check if there are cached blocks that are
                // at heights we previously scanned? Check scanning flow again.
                return Ok(());
            }
        };
        let block: CompactBlock = parse_from_bytes(&assumed_correct.data)?;
        (block.height as i32, block.prev_hash())
    };
    for row in rows {
        let row = row?;
        // Scanned blocks MUST be height-sequential.
        if row.height != (last_height - 1) {
            return Err(Error(ErrorKind::InvalidHeight(last_height - 1, row.height)));
        }
        last_height = row.height;
        let block: CompactBlock = parse_from_bytes(&row.data)?;
        // Cached blocks MUST be hash-chained.
        if block.hash() != last_prev_hash {
            return Err(Error(ErrorKind::InvalidChain(
                last_height,
                ChainInvalidCause::PrevHashMismatch,
            )));
        }
        last_prev_hash = block.prev_hash();
    }
    if have_scanned {
        // Cached blocks MUST hash-chain to the last scanned block.
        let last_scanned_hash = data.query_row(
            "SELECT hash FROM blocks WHERE height = ?",
            &[last_scanned_height],
            |row| row.get::<_, Vec<_>>(0),
        )?;
        if &last_scanned_hash[..] != &last_prev_hash.0[..] {
            return Err(Error(ErrorKind::InvalidChain(
                last_scanned_height,
                ChainInvalidCause::PrevHashMismatch,
            )));
        }
    }
    // All good!
    Ok(())
 }
 /// Rewinds the data database to the given height.
 ///
 /// If the requested height is greater than or equal to the height of the last scanned
 /// block, this function does nothing.
 pub fn rewind_to_height<P: AsRef<Path>>(db_data: P, height: i32) -> Result<(), Error> {
    let data = Connection::open(db_data)?;
    // Recall where we synced up to previously.
    // If we have never synced, use Sapling activation height.
    let last_scanned_height =
        data.query_row("SELECT MAX(height) FROM blocks", NO_PARAMS, |row| {
            row.get(0).or(Ok(SAPLING_ACTIVATION_HEIGHT - 1))
        })?;
    if height >= last_scanned_height {
        // Nothing to do.
        return Ok(());
    }
    // Start an SQL transaction for rewinding.
    data.execute("BEGIN IMMEDIATE", NO_PARAMS)?;
    // Decrement witnesses.
    data.execute("DELETE FROM sapling_witnesses WHERE block > ?", &[height])?;
    // Un-mine transactions.
    data.execute(
        "UPDATE transactions SET block = NULL, tx_index = NULL WHERE block > ?",
        &[height],
    )?;
    // Now that they aren't depended on, delete scanned blocks.
    data.execute("DELETE FROM blocks WHERE height > ?", &[height])?;
    // Commit the SQL transaction, rewinding atomically.
    data.execute("COMMIT", NO_PARAMS)?;
    Ok(())
 }
 #[cfg(test)]
 mod tests {
    use tempfile::NamedTempFile;
    use zcash_primitives::{
        block::BlockHash,
        transaction::components::Amount,
        zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    };
    use super::{rewind_to_height, validate_combined_chain};
    use crate::{
        error::ErrorKind,
        init::{init_accounts_table, init_cache_database, init_data_database},
        query::get_balance,
        scan::scan_cached_blocks,
        tests::{fake_compact_block, insert_into_cache},
        SAPLING_ACTIVATION_HEIGHT,
    };
    #[test]
    fn valid_chain_states() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Empty chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
        // Create a fake CompactBlock sending value to the address
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            Amount::from_u64(5).unwrap(),
        );
        insert_into_cache(db_cache, &cb);
        // Cache-only chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
        // Scan the cache
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Data-only chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
        // Create a second fake CompactBlock sending more value to the address
        let (cb2, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 1,
            cb.hash(),
            extfvk,
            Amount::from_u64(7).unwrap(),
        );
        insert_into_cache(db_cache, &cb2);
        // Data+cache chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
        // Scan the cache again
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Data-only chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
    }
    #[test]
    fn invalid_chain_cache_disconnected() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Create some fake CompactBlocks
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            Amount::from_u64(5).unwrap(),
        );
        let (cb2, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 1,
            cb.hash(),
            extfvk.clone(),
            Amount::from_u64(7).unwrap(),
        );
        insert_into_cache(db_cache, &cb);
        insert_into_cache(db_cache, &cb2);
        // Scan the cache
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Data-only chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
        // Create more fake CompactBlocks that don't connect to the scanned ones
        let (cb3, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 2,
            BlockHash([1; 32]),
            extfvk.clone(),
            Amount::from_u64(8).unwrap(),
        );
        let (cb4, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 3,
            cb3.hash(),
            extfvk.clone(),
            Amount::from_u64(3).unwrap(),
        );
        insert_into_cache(db_cache, &cb3);
        insert_into_cache(db_cache, &cb4);
        // Data+cache chain should be invalid at the data/cache boundary
        match validate_combined_chain(db_cache, db_data) {
            Err(e) => match e.kind() {
                ErrorKind::InvalidChain(upper_bound, _) => {
                    assert_eq!(*upper_bound, SAPLING_ACTIVATION_HEIGHT + 1)
                }
                _ => panic!(),
            },
            _ => panic!(),
        }
    }
    #[test]
    fn invalid_chain_cache_reorg() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Create some fake CompactBlocks
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            Amount::from_u64(5).unwrap(),
        );
        let (cb2, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 1,
            cb.hash(),
            extfvk.clone(),
            Amount::from_u64(7).unwrap(),
        );
        insert_into_cache(db_cache, &cb);
        insert_into_cache(db_cache, &cb2);
        // Scan the cache
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Data-only chain should be valid
        validate_combined_chain(db_cache, db_data).unwrap();
        // Create more fake CompactBlocks that contain a reorg
        let (cb3, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 2,
            cb2.hash(),
            extfvk.clone(),
            Amount::from_u64(8).unwrap(),
        );
        let (cb4, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 3,
            BlockHash([1; 32]),
            extfvk.clone(),
            Amount::from_u64(3).unwrap(),
        );
        insert_into_cache(db_cache, &cb3);
        insert_into_cache(db_cache, &cb4);
        // Data+cache chain should be invalid inside the cache
        match validate_combined_chain(db_cache, db_data) {
            Err(e) => match e.kind() {
                ErrorKind::InvalidChain(upper_bound, _) => {
                    assert_eq!(*upper_bound, SAPLING_ACTIVATION_HEIGHT + 2)
                }
                _ => panic!(),
            },
            _ => panic!(),
        }
    }
    #[test]
    fn data_db_rewinding() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Account balance should be zero
        assert_eq!(get_balance(db_data, 0).unwrap(), Amount::zero());
        // Create fake CompactBlocks sending value to the address
        let value = Amount::from_u64(5).unwrap();
        let value2 = Amount::from_u64(7).unwrap();
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            value,
        );
        let (cb2, _) = fake_compact_block(SAPLING_ACTIVATION_HEIGHT + 1, cb.hash(), extfvk, value2);
        insert_into_cache(db_cache, &cb);
        insert_into_cache(db_cache, &cb2);
        // Scan the cache
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Account balance should reflect both received notes
        assert_eq!(get_balance(db_data, 0).unwrap(), value + value2);
        // "Rewind" to height of last scanned block
        rewind_to_height(db_data, SAPLING_ACTIVATION_HEIGHT + 1).unwrap();
        // Account balance should be unaltered
        assert_eq!(get_balance(db_data, 0).unwrap(), value + value2);
        // Rewind so that one block is dropped
        rewind_to_height(db_data, SAPLING_ACTIVATION_HEIGHT).unwrap();
        // Account balance should only contain the first received note
        assert_eq!(get_balance(db_data, 0).unwrap(), value);
    }
 }
--- a/zcash_client_sqlite/src/error.rs
+++ b/zcash_client_sqlite/src/error.rs
@@ -1,132 +0,0 @@
 use std::error;
 use std::fmt;
 use zcash_primitives::{
    sapling::Node,
    transaction::{builder, TxId},
 };
 #[derive(Debug)]
 pub enum ErrorKind {
    CorruptedData(&'static str),
    IncorrectHRPExtFVK,
    InsufficientBalance(u64, u64),
    InvalidChain(i32, crate::chain::ChainInvalidCause),
    InvalidExtSK(u32),
    InvalidHeight(i32, i32),
    InvalidMemo(std::str::Utf8Error),
    InvalidNewWitnessAnchor(usize, TxId, i32, Node),
    InvalidNote,
    InvalidWitnessAnchor(i64, i32),
    ScanRequired,
    TableNotEmpty,
    Bech32(bech32::Error),
    Base58(bs58::decode::DecodeError),
    Builder(builder::Error),
    Database(rusqlite::Error),
    Io(std::io::Error),
    Protobuf(protobuf::ProtobufError),
 }
 #[derive(Debug)]
 pub struct Error(pub(crate) ErrorKind);
 impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match &self.0 {
            ErrorKind::CorruptedData(reason) => write!(f, "Data DB is corrupted: {}", reason),
            ErrorKind::IncorrectHRPExtFVK => write!(f, "Incorrect HRP for extfvk"),
            ErrorKind::InsufficientBalance(have, need) => write!(
                f,
                "Insufficient balance (have {}, need {} including fee)",
                have, need
            ),
            ErrorKind::InvalidChain(upper_bound, cause) => {
                write!(f, "Invalid chain (upper bound: {}): {:?}", upper_bound, cause)
            }
            ErrorKind::InvalidExtSK(account) => {
                write!(f, "Incorrect ExtendedSpendingKey for account {}", account)
            }
            ErrorKind::InvalidHeight(expected, actual) => write!(
                f,
                "Expected height of next CompactBlock to be {}, but was {}",
                expected, actual
            ),
            ErrorKind::InvalidMemo(e) => write!(f, "{}", e),
            ErrorKind::InvalidNewWitnessAnchor(output, txid, last_height, anchor) => write!(
                f,
                "New witness for output {} in tx {} has incorrect anchor after scanning block {}: {:?}",
                output, txid, last_height, anchor,
            ),
            ErrorKind::InvalidNote => write!(f, "Invalid note"),
            ErrorKind::InvalidWitnessAnchor(id_note, last_height) => write!(
                f,
                "Witness for note {} has incorrect anchor after scanning block {}",
                id_note, last_height
            ),
            ErrorKind::ScanRequired => write!(f, "Must scan blocks first"),
            ErrorKind::TableNotEmpty => write!(f, "Table is not empty"),
            ErrorKind::Bech32(e) => write!(f, "{}", e),
            ErrorKind::Base58(e) => write!(f, "{}", e),
            ErrorKind::Builder(e) => write!(f, "{:?}", e),
            ErrorKind::Database(e) => write!(f, "{}", e),
            ErrorKind::Io(e) => write!(f, "{}", e),
            ErrorKind::Protobuf(e) => write!(f, "{}", e),
        }
    }
 }
 impl error::Error for Error {
    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
        match &self.0 {
            ErrorKind::InvalidMemo(e) => Some(e),
            ErrorKind::Bech32(e) => Some(e),
            ErrorKind::Builder(e) => Some(e),
            ErrorKind::Database(e) => Some(e),
            ErrorKind::Io(e) => Some(e),
            ErrorKind::Protobuf(e) => Some(e),
            _ => None,
        }
    }
 }
 impl From<bech32::Error> for Error {
    fn from(e: bech32::Error) -> Self {
        Error(ErrorKind::Bech32(e))
    }
 }
 impl From<bs58::decode::DecodeError> for Error {
    fn from(e: bs58::decode::DecodeError) -> Self {
        Error(ErrorKind::Base58(e))
    }
 }
 impl From<builder::Error> for Error {
    fn from(e: builder::Error) -> Self {
        Error(ErrorKind::Builder(e))
    }
 }
 impl From<rusqlite::Error> for Error {
    fn from(e: rusqlite::Error) -> Self {
        Error(ErrorKind::Database(e))
    }
 }
 impl From<std::io::Error> for Error {
    fn from(e: std::io::Error) -> Self {
        Error(ErrorKind::Io(e))
    }
 }
 impl From<protobuf::ProtobufError> for Error {
    fn from(e: protobuf::ProtobufError) -> Self {
        Error(ErrorKind::Protobuf(e))
    }
 }
 impl Error {
    pub fn kind(&self) -> &ErrorKind {
        &self.0
    }
 }
--- a/zcash_client_sqlite/src/init.rs
+++ b/zcash_client_sqlite/src/init.rs
@@ -1,303 +0,0 @@
 //! Functions for initializing the various databases.
 use rusqlite::{types::ToSql, Connection, NO_PARAMS};
 use std::path::Path;
 use zcash_client_backend::encoding::encode_extended_full_viewing_key;
 use zcash_primitives::{block::BlockHash, zip32::ExtendedFullViewingKey};
 use crate::{
    address_from_extfvk,
    error::{Error, ErrorKind},
    HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
 };
 /// Sets up the internal structure of the cache database.
 ///
 /// # Examples
 ///
 /// ```
 /// use tempfile::NamedTempFile;
 /// use zcash_client_sqlite::init::init_cache_database;
 ///
 /// let data_file = NamedTempFile::new().unwrap();
 /// let db_cache = data_file.path();
 /// init_cache_database(&db_cache).unwrap();
 /// ```
 pub fn init_cache_database<P: AsRef<Path>>(db_cache: P) -> Result<(), Error> {
    let cache = Connection::open(db_cache)?;
    cache.execute(
        "CREATE TABLE IF NOT EXISTS compactblocks (
            height INTEGER PRIMARY KEY,
            data BLOB NOT NULL
        )",
        NO_PARAMS,
    )?;
    Ok(())
 }
 /// Sets up the internal structure of the data database.
 ///
 /// # Examples
 ///
 /// ```
 /// use tempfile::NamedTempFile;
 /// use zcash_client_sqlite::init::init_data_database;
 ///
 /// let data_file = NamedTempFile::new().unwrap();
 /// let db_data = data_file.path();
 /// init_data_database(&db_data).unwrap();
 /// ```
 pub fn init_data_database<P: AsRef<Path>>(db_data: P) -> Result<(), Error> {
    let data = Connection::open(db_data)?;
    data.execute(
        "CREATE TABLE IF NOT EXISTS accounts (
            account INTEGER PRIMARY KEY,
            extfvk TEXT NOT NULL,
            address TEXT NOT NULL
        )",
        NO_PARAMS,
    )?;
    data.execute(
        "CREATE TABLE IF NOT EXISTS blocks (
            height INTEGER PRIMARY KEY,
            hash BLOB NOT NULL,
            time INTEGER NOT NULL,
            sapling_tree BLOB NOT NULL
        )",
        NO_PARAMS,
    )?;
    data.execute(
        "CREATE TABLE IF NOT EXISTS transactions (
            id_tx INTEGER PRIMARY KEY,
            txid BLOB NOT NULL UNIQUE,
            created TEXT,
            block INTEGER,
            tx_index INTEGER,
            expiry_height INTEGER,
            raw BLOB,
            FOREIGN KEY (block) REFERENCES blocks(height)
        )",
        NO_PARAMS,
    )?;
    data.execute(
        "CREATE TABLE IF NOT EXISTS received_notes (
            id_note INTEGER PRIMARY KEY,
            tx INTEGER NOT NULL,
            output_index INTEGER NOT NULL,
            account INTEGER NOT NULL,
            diversifier BLOB NOT NULL,
            value INTEGER NOT NULL,
            rcm BLOB NOT NULL,
            nf BLOB NOT NULL UNIQUE,
            is_change BOOLEAN NOT NULL,
            memo BLOB,
            spent INTEGER,
            FOREIGN KEY (tx) REFERENCES transactions(id_tx),
            FOREIGN KEY (account) REFERENCES accounts(account),
            FOREIGN KEY (spent) REFERENCES transactions(id_tx),
            CONSTRAINT tx_output UNIQUE (tx, output_index)
        )",
        NO_PARAMS,
    )?;
    data.execute(
        "CREATE TABLE IF NOT EXISTS sapling_witnesses (
            id_witness INTEGER PRIMARY KEY,
            note INTEGER NOT NULL,
            block INTEGER NOT NULL,
            witness BLOB NOT NULL,
            FOREIGN KEY (note) REFERENCES received_notes(id_note),
            FOREIGN KEY (block) REFERENCES blocks(height),
            CONSTRAINT witness_height UNIQUE (note, block)
        )",
        NO_PARAMS,
    )?;
    data.execute(
        "CREATE TABLE IF NOT EXISTS sent_notes (
            id_note INTEGER PRIMARY KEY,
            tx INTEGER NOT NULL,
            output_index INTEGER NOT NULL,
            from_account INTEGER NOT NULL,
            address TEXT NOT NULL,
            value INTEGER NOT NULL,
            memo BLOB,
            FOREIGN KEY (tx) REFERENCES transactions(id_tx),
            FOREIGN KEY (from_account) REFERENCES accounts(account),
            CONSTRAINT tx_output UNIQUE (tx, output_index)
        )",
        NO_PARAMS,
    )?;
    Ok(())
 }
 /// Initialises the data database with the given [`ExtendedFullViewingKey`]s.
 ///
 /// The [`ExtendedFullViewingKey`]s are stored internally and used by other APIs such as
 /// [`get_address`], [`scan_cached_blocks`], and [`create_to_address`]. `extfvks` **MUST**
 /// be arranged in account-order; that is, the [`ExtendedFullViewingKey`] for ZIP 32
 /// account `i` **MUST** be at `extfvks[i]`.
 ///
 /// # Examples
 ///
 /// ```
 /// use tempfile::NamedTempFile;
 /// use zcash_client_sqlite::init::{init_accounts_table, init_data_database};
 /// use zcash_primitives::zip32::{ExtendedFullViewingKey, ExtendedSpendingKey};
 ///
 /// let data_file = NamedTempFile::new().unwrap();
 /// let db_data = data_file.path();
 /// init_data_database(&db_data).unwrap();
 ///
 /// let extsk = ExtendedSpendingKey::master(&[]);
 /// let extfvks = [ExtendedFullViewingKey::from(&extsk)];
 /// init_accounts_table(&db_data, &extfvks).unwrap();
 /// ```
 ///
 /// [`get_address`]: crate::query::get_address
 /// [`scan_cached_blocks`]: crate::scan::scan_cached_blocks
 /// [`create_to_address`]: crate::transact::create_to_address
 pub fn init_accounts_table<P: AsRef<Path>>(
    db_data: P,
    extfvks: &[ExtendedFullViewingKey],
 ) -> Result<(), Error> {
    let data = Connection::open(db_data)?;
    let mut empty_check = data.prepare("SELECT * FROM accounts LIMIT 1")?;
    if empty_check.exists(NO_PARAMS)? {
        return Err(Error(ErrorKind::TableNotEmpty));
    }
    // Insert accounts atomically
    data.execute("BEGIN IMMEDIATE", NO_PARAMS)?;
    for (account, extfvk) in extfvks.iter().enumerate() {
        let address = address_from_extfvk(extfvk);
        let extfvk =
            encode_extended_full_viewing_key(HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY, extfvk);
        data.execute(
            "INSERT INTO accounts (account, extfvk, address)
            VALUES (?, ?, ?)",
            &[
                (account as u32).to_sql()?,
                extfvk.to_sql()?,
                address.to_sql()?,
            ],
        )?;
    }
    data.execute("COMMIT", NO_PARAMS)?;
    Ok(())
 }
 /// Initialises the data database with the given block.
 ///
 /// This enables a newly-created database to be immediately-usable, without needing to
 /// synchronise historic blocks.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::init::init_blocks_table;
 /// use zcash_primitives::block::BlockHash;
 ///
 /// // The block height.
 /// let height = 500_000;
 /// // The hash of the block header.
 /// let hash = BlockHash([0; 32]);
 /// // The nTime field from the block header.
 /// let time = 12_3456_7890;
 /// // The serialized Sapling commitment tree as of this block.
 /// // Pre-compute and hard-code, or obtain from a service.
 /// let sapling_tree = &[];
 ///
 /// init_blocks_table("/path/to/data.db", height, hash, time, sapling_tree);
 /// ```
 pub fn init_blocks_table<P: AsRef<Path>>(
    db_data: P,
    height: i32,
    hash: BlockHash,
    time: u32,
    sapling_tree: &[u8],
 ) -> Result<(), Error> {
    let data = Connection::open(db_data)?;
    let mut empty_check = data.prepare("SELECT * FROM blocks LIMIT 1")?;
    if empty_check.exists(NO_PARAMS)? {
        return Err(Error(ErrorKind::TableNotEmpty));
    }
    data.execute(
        "INSERT INTO blocks (height, hash, time, sapling_tree)
        VALUES (?, ?, ?, ?)",
        &[
            height.to_sql()?,
            hash.0.to_sql()?,
            time.to_sql()?,
            sapling_tree.to_sql()?,
        ],
    )?;
    Ok(())
 }
 #[cfg(test)]
 mod tests {
    use tempfile::NamedTempFile;
    use zcash_client_backend::encoding::decode_payment_address;
    use zcash_primitives::{
        block::BlockHash,
        zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    };
    use super::{init_accounts_table, init_blocks_table, init_data_database};
    use crate::{query::get_address, HRP_SAPLING_PAYMENT_ADDRESS};
    #[test]
    fn init_accounts_table_only_works_once() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // We can call the function as many times as we want with no data
        init_accounts_table(&db_data, &[]).unwrap();
        init_accounts_table(&db_data, &[]).unwrap();
        // First call with data should initialise the accounts table
        let extfvks = [ExtendedFullViewingKey::from(&ExtendedSpendingKey::master(
            &[],
        ))];
        init_accounts_table(&db_data, &extfvks).unwrap();
        // Subsequent calls should return an error
        init_accounts_table(&db_data, &[]).unwrap_err();
        init_accounts_table(&db_data, &extfvks).unwrap_err();
    }
    #[test]
    fn init_blocks_table_only_works_once() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // First call with data should initialise the blocks table
        init_blocks_table(&db_data, 1, BlockHash([1; 32]), 1, &[]).unwrap();
        // Subsequent calls should return an error
        init_blocks_table(&db_data, 2, BlockHash([2; 32]), 2, &[]).unwrap_err();
    }
    #[test]
    fn init_accounts_table_stores_correct_address() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvks = [ExtendedFullViewingKey::from(&extsk)];
        init_accounts_table(&db_data, &extfvks).unwrap();
        // The account's address should be in the data DB
        let addr = get_address(&db_data, 0).unwrap();
        let pa = decode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, &addr).unwrap();
        assert_eq!(pa.unwrap(), extsk.default_address().unwrap().1);
    }
 }
--- a/zcash_client_sqlite/src/lib.rs
+++ b/zcash_client_sqlite/src/lib.rs
@@ -1,262 +0,0 @@
 //! *An SQLite-based Zcash light client.*
 //!
 //! `zcash_client_backend` contains a set of APIs that collectively implement an
 //! SQLite-based light client for the Zcash network.
 //!
 //! # Design
 //!
 //! The light client is built around two SQLite databases:
 //!
 //! - A cache database, used to inform the light client about new [`CompactBlock`]s. It is
 //!   read-only within all light client APIs *except* for [`init_cache_database`] which
 //!   can be used to initialize the database.
 //!
 //! - A data database, where the light client's state is stored. It is read-write within
 //!   the light client APIs, and **assumed to be read-only outside these APIs**. Callers
 //!   **MUST NOT** write to the database without using these APIs. Callers **MAY** read
 //!   the database directly in order to extract information for display to users.
 //!
 //! # Features
 //!
 //! The `mainnet` feature configures the light client for use with the Zcash mainnet. By
 //! default, the light client is configured for use with the Zcash testnet.
 //!
 //! [`CompactBlock`]: zcash_client_backend::proto::compact_formats::CompactBlock
 //! [`init_cache_database`]: crate::init::init_cache_database
 use rusqlite::{Connection, NO_PARAMS};
 use std::cmp;
 use zcash_client_backend::encoding::encode_payment_address;
 use zcash_primitives::zip32::ExtendedFullViewingKey;
 #[cfg(feature = "mainnet")]
 use zcash_client_backend::constants::mainnet::{
    HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY, HRP_SAPLING_PAYMENT_ADDRESS,
 };
 #[cfg(not(feature = "mainnet"))]
 use zcash_client_backend::constants::testnet::{
    HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY, HRP_SAPLING_PAYMENT_ADDRESS,
 };
 pub mod address;
 pub mod chain;
 pub mod error;
 pub mod init;
 pub mod query;
 pub mod scan;
 pub mod transact;
 const ANCHOR_OFFSET: u32 = 10;
 #[cfg(feature = "mainnet")]
 const SAPLING_ACTIVATION_HEIGHT: i32 = 227_520;
 #[cfg(not(feature = "mainnet"))]
 const SAPLING_ACTIVATION_HEIGHT: i32 = 280_000;
 fn address_from_extfvk(extfvk: &ExtendedFullViewingKey) -> String {
    let addr = extfvk.default_address().unwrap().1;
    encode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, &addr)
 }
 /// Determines the target height for a transaction, and the height from which to
 /// select anchors, based on the current synchronised block chain.
 fn get_target_and_anchor_heights(data: &Connection) -> Result<(u32, u32), error::Error> {
    data.query_row_and_then(
        "SELECT MIN(height), MAX(height) FROM blocks",
        NO_PARAMS,
        |row| match (row.get::<_, u32>(0), row.get::<_, u32>(1)) {
            // If there are no blocks, the query returns NULL.
            (Err(rusqlite::Error::InvalidColumnType(_, _, _)), _)
            | (_, Err(rusqlite::Error::InvalidColumnType(_, _, _))) => {
                Err(error::Error(error::ErrorKind::ScanRequired))
            }
            (Err(e), _) | (_, Err(e)) => Err(e.into()),
            (Ok(min_height), Ok(max_height)) => {
                let target_height = max_height + 1;
                // Select an anchor ANCHOR_OFFSET back from the target block,
                // unless that would be before the earliest block we have.
                let anchor_height =
                    cmp::max(target_height.saturating_sub(ANCHOR_OFFSET), min_height);
                Ok((target_height, anchor_height))
            }
        },
    )
 }
 #[cfg(test)]
 mod tests {
    use ff::{Field, PrimeField, PrimeFieldRepr};
    use pairing::bls12_381::Bls12;
    use protobuf::Message;
    use rand_core::RngCore;
    use rand_os::OsRng;
    use rusqlite::{types::ToSql, Connection};
    use std::path::Path;
    use zcash_client_backend::proto::compact_formats::{
        CompactBlock, CompactOutput, CompactSpend, CompactTx,
    };
    use zcash_primitives::{
        block::BlockHash,
        jubjub::fs::Fs,
        note_encryption::{Memo, SaplingNoteEncryption},
        primitives::{Note, PaymentAddress},
        transaction::components::Amount,
        zip32::ExtendedFullViewingKey,
        JUBJUB,
    };
    /// Create a fake CompactBlock at the given height, containing a single output paying
    /// the given address. Returns the CompactBlock and the nullifier for the new note.
    pub(crate) fn fake_compact_block(
        height: i32,
        prev_hash: BlockHash,
        extfvk: ExtendedFullViewingKey,
        value: Amount,
    ) -> (CompactBlock, Vec<u8>) {
        let to = extfvk.default_address().unwrap().1;
        // Create a fake Note for the account
        let mut rng = OsRng;
        let note = Note {
            g_d: to.diversifier.g_d::<Bls12>(&JUBJUB).unwrap(),
            pk_d: to.pk_d.clone(),
            value: value.into(),
            r: Fs::random(&mut rng),
        };
        let encryptor = SaplingNoteEncryption::new(
            extfvk.fvk.ovk,
            note.clone(),
            to.clone(),
            Memo::default(),
            &mut rng,
        );
        let mut cmu = vec![];
        note.cm(&JUBJUB).into_repr().write_le(&mut cmu).unwrap();
        let mut epk = vec![];
        encryptor.epk().write(&mut epk).unwrap();
        let enc_ciphertext = encryptor.encrypt_note_plaintext();
        // Create a fake CompactBlock containing the note
        let mut cout = CompactOutput::new();
        cout.set_cmu(cmu);
        cout.set_epk(epk);
        cout.set_ciphertext(enc_ciphertext[..52].to_vec());
        let mut ctx = CompactTx::new();
        let mut txid = vec![0; 32];
        rng.fill_bytes(&mut txid);
        ctx.set_hash(txid);
        ctx.outputs.push(cout);
        let mut cb = CompactBlock::new();
        cb.set_height(height as u64);
        cb.hash.resize(32, 0);
        rng.fill_bytes(&mut cb.hash);
        cb.prevHash.extend_from_slice(&prev_hash.0);
        cb.vtx.push(ctx);
        (cb, note.nf(&extfvk.fvk.vk, 0, &JUBJUB))
    }
    /// Create a fake CompactBlock at the given height, spending a single note from the
    /// given address.
    pub(crate) fn fake_compact_block_spending(
        height: i32,
        prev_hash: BlockHash,
        (nf, in_value): (Vec<u8>, Amount),
        extfvk: ExtendedFullViewingKey,
        to: PaymentAddress<Bls12>,
        value: Amount,
    ) -> CompactBlock {
        let mut rng = OsRng;
        // Create a fake CompactBlock containing the note
        let mut cspend = CompactSpend::new();
        cspend.set_nf(nf);
        let mut ctx = CompactTx::new();
        let mut txid = vec![0; 32];
        rng.fill_bytes(&mut txid);
        ctx.set_hash(txid);
        ctx.spends.push(cspend);
        // Create a fake Note for the payment
        ctx.outputs.push({
            let note = Note {
                g_d: to.diversifier.g_d::<Bls12>(&JUBJUB).unwrap(),
                pk_d: to.pk_d.clone(),
                value: value.into(),
                r: Fs::random(&mut rng),
            };
            let encryptor = SaplingNoteEncryption::new(
                extfvk.fvk.ovk,
                note.clone(),
                to,
                Memo::default(),
                &mut rng,
            );
            let mut cmu = vec![];
            note.cm(&JUBJUB).into_repr().write_le(&mut cmu).unwrap();
            let mut epk = vec![];
            encryptor.epk().write(&mut epk).unwrap();
            let enc_ciphertext = encryptor.encrypt_note_plaintext();
            let mut cout = CompactOutput::new();
            cout.set_cmu(cmu);
            cout.set_epk(epk);
            cout.set_ciphertext(enc_ciphertext[..52].to_vec());
            cout
        });
        // Create a fake Note for the change
        ctx.outputs.push({
            let change_addr = extfvk.default_address().unwrap().1;
            let note = Note {
                g_d: change_addr.diversifier.g_d::<Bls12>(&JUBJUB).unwrap(),
                pk_d: change_addr.pk_d.clone(),
                value: (in_value - value).into(),
                r: Fs::random(&mut rng),
            };
            let encryptor = SaplingNoteEncryption::new(
                extfvk.fvk.ovk,
                note.clone(),
                change_addr,
                Memo::default(),
                &mut rng,
            );
            let mut cmu = vec![];
            note.cm(&JUBJUB).into_repr().write_le(&mut cmu).unwrap();
            let mut epk = vec![];
            encryptor.epk().write(&mut epk).unwrap();
            let enc_ciphertext = encryptor.encrypt_note_plaintext();
            let mut cout = CompactOutput::new();
            cout.set_cmu(cmu);
            cout.set_epk(epk);
            cout.set_ciphertext(enc_ciphertext[..52].to_vec());
            cout
        });
        let mut cb = CompactBlock::new();
        cb.set_height(height as u64);
        cb.hash.resize(32, 0);
        rng.fill_bytes(&mut cb.hash);
        cb.prevHash.extend_from_slice(&prev_hash.0);
        cb.vtx.push(ctx);
        cb
    }
    /// Insert a fake CompactBlock into the cache DB.
    pub(crate) fn insert_into_cache<P: AsRef<Path>>(db_cache: P, cb: &CompactBlock) {
        let cb_bytes = cb.write_to_bytes().unwrap();
        let cache = Connection::open(&db_cache).unwrap();
        cache
            .prepare("INSERT INTO compactblocks (height, data) VALUES (?, ?)")
            .unwrap()
            .execute(&[
                (cb.height as i32).to_sql().unwrap(),
                cb_bytes.to_sql().unwrap(),
            ])
            .unwrap();
    }
 }
--- a/zcash_client_sqlite/src/query.rs
+++ b/zcash_client_sqlite/src/query.rs
@@ -1,201 +0,0 @@
 //! Functions for querying information in the data database.
 use rusqlite::Connection;
 use std::path::Path;
 use zcash_primitives::{note_encryption::Memo, transaction::components::Amount};
 use crate::{
    error::{Error, ErrorKind},
    get_target_and_anchor_heights,
 };
 /// Returns the address for the account.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::query::get_address;
 ///
 /// let addr = get_address("/path/to/data.db", 0);
 /// ```
 pub fn get_address<P: AsRef<Path>>(db_data: P, account: u32) -> Result<String, Error> {
    let data = Connection::open(db_data)?;
    let addr = data.query_row(
        "SELECT address FROM accounts
        WHERE account = ?",
        &[account],
        |row| row.get(0),
    )?;
    Ok(addr)
 }
 /// Returns the balance for the account, including all mined unspent notes that we know
 /// about.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::query::get_balance;
 ///
 /// let addr = get_balance("/path/to/data.db", 0);
 /// ```
 pub fn get_balance<P: AsRef<Path>>(db_data: P, account: u32) -> Result<Amount, Error> {
    let data = Connection::open(db_data)?;
    let balance = data.query_row(
        "SELECT SUM(value) FROM received_notes
        INNER JOIN transactions ON transactions.id_tx = received_notes.tx
        WHERE account = ? AND spent IS NULL AND transactions.block IS NOT NULL",
        &[account],
        |row| row.get(0).or(Ok(0)),
    )?;
    match Amount::from_i64(balance) {
        Ok(amount) if !amount.is_negative() => Ok(amount),
        _ => Err(Error(ErrorKind::CorruptedData(
            "Sum of values in received_notes is out of range",
        ))),
    }
 }
 /// Returns the verified balance for the account, which ignores notes that have been
 /// received too recently and are not yet deemed spendable.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::query::get_verified_balance;
 ///
 /// let addr = get_verified_balance("/path/to/data.db", 0);
 /// ```
 pub fn get_verified_balance<P: AsRef<Path>>(db_data: P, account: u32) -> Result<Amount, Error> {
    let data = Connection::open(db_data)?;
    let (_, anchor_height) = get_target_and_anchor_heights(&data)?;
    let balance = data.query_row(
        "SELECT SUM(value) FROM received_notes
        INNER JOIN transactions ON transactions.id_tx = received_notes.tx
        WHERE account = ? AND spent IS NULL AND transactions.block <= ?",
        &[account, anchor_height],
        |row| row.get(0).or(Ok(0)),
    )?;
    match Amount::from_i64(balance) {
        Ok(amount) if !amount.is_negative() => Ok(amount),
        _ => Err(Error(ErrorKind::CorruptedData(
            "Sum of values in received_notes is out of range",
        ))),
    }
 }
 /// Returns the memo for a received note, if it is known and a valid UTF-8 string.
 ///
 /// The note is identified by its row index in the `received_notes` table within the data
 /// database.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::query::get_received_memo_as_utf8;
 ///
 /// let memo = get_received_memo_as_utf8("/path/to/data.db", 27);
 pub fn get_received_memo_as_utf8<P: AsRef<Path>>(
    db_data: P,
    id_note: i64,
 ) -> Result<Option<String>, Error> {
    let data = Connection::open(db_data)?;
    let memo: Vec<_> = data.query_row(
        "SELECT memo FROM received_notes
        WHERE id_note = ?",
        &[id_note],
        |row| row.get(0),
    )?;
    match Memo::from_bytes(&memo) {
        Some(memo) => match memo.to_utf8() {
            Some(Ok(res)) => Ok(Some(res)),
            Some(Err(e)) => Err(Error(ErrorKind::InvalidMemo(e))),
            None => Ok(None),
        },
        None => Ok(None),
    }
 }
 /// Returns the memo for a sent note, if it is known and a valid UTF-8 string.
 ///
 /// The note is identified by its row index in the `sent_notes` table within the data
 /// database.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::query::get_sent_memo_as_utf8;
 ///
 /// let memo = get_sent_memo_as_utf8("/path/to/data.db", 12);
 pub fn get_sent_memo_as_utf8<P: AsRef<Path>>(
    db_data: P,
    id_note: i64,
 ) -> Result<Option<String>, Error> {
    let data = Connection::open(db_data)?;
    let memo: Vec<_> = data.query_row(
        "SELECT memo FROM sent_notes
        WHERE id_note = ?",
        &[id_note],
        |row| row.get(0),
    )?;
    match Memo::from_bytes(&memo) {
        Some(memo) => match memo.to_utf8() {
            Some(Ok(res)) => Ok(Some(res)),
            Some(Err(e)) => Err(Error(ErrorKind::InvalidMemo(e))),
            None => Ok(None),
        },
        None => Ok(None),
    }
 }
 #[cfg(test)]
 mod tests {
    use tempfile::NamedTempFile;
    use zcash_primitives::{
        transaction::components::Amount,
        zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    };
    use super::{get_address, get_balance, get_verified_balance};
    use crate::{
        error::ErrorKind,
        init::{init_accounts_table, init_data_database},
    };
    #[test]
    fn empty_database_has_no_balance() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvks = [ExtendedFullViewingKey::from(&extsk)];
        init_accounts_table(&db_data, &extfvks).unwrap();
        // The account should be empty
        assert_eq!(get_balance(db_data, 0).unwrap(), Amount::zero());
        // The account should have no verified balance, as we haven't scanned any blocks
        let e = get_verified_balance(db_data, 0).unwrap_err();
        match e.kind() {
            ErrorKind::ScanRequired => (),
            _ => panic!("Unexpected error: {:?}", e),
        }
        // An invalid account has zero balance
        assert!(get_address(db_data, 1).is_err());
        assert_eq!(get_balance(db_data, 1).unwrap(), Amount::zero());
    }
 }
--- a/zcash_client_sqlite/src/scan.rs
+++ b/zcash_client_sqlite/src/scan.rs
@@ -1,500 +0,0 @@
 //! Functions for scanning the chain and extracting relevant information.
 use ff::{PrimeField, PrimeFieldRepr};
 use protobuf::parse_from_bytes;
 use rusqlite::{types::ToSql, Connection, NO_PARAMS};
 use std::path::Path;
 use zcash_client_backend::{
    encoding::decode_extended_full_viewing_key, proto::compact_formats::CompactBlock,
    welding_rig::scan_block,
 };
 use zcash_primitives::{
    merkle_tree::{CommitmentTree, IncrementalWitness},
    sapling::Node,
    JUBJUB,
 };
 use crate::{
    error::{Error, ErrorKind},
    HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY, SAPLING_ACTIVATION_HEIGHT,
 };
 struct CompactBlockRow {
    height: i32,
    data: Vec<u8>,
 }
 #[derive(Clone)]
 struct WitnessRow {
    id_note: i64,
    witness: IncrementalWitness<Node>,
 }
 /// Scans new blocks added to the cache for any transactions received by the tracked
 /// accounts.
 ///
 /// This function pays attention only to cached blocks with heights greater than the
 /// highest scanned block in `db_data`. Cached blocks with lower heights are not verified
 /// against previously-scanned blocks. In particular, this function **assumes** that the
 /// caller is handling rollbacks.
 ///
 /// For brand-new light client databases, this function starts scanning from the Sapling
 /// activation height. This height can be fast-forwarded to a more recent block by calling
 /// [`init_blocks_table`] before this function.
 ///
 /// Scanned blocks are required to be height-sequential. If a block is missing from the
 /// cache, an error will be returned with kind [`ErrorKind::InvalidHeight`].
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_sqlite::scan::scan_cached_blocks;
 ///
 /// scan_cached_blocks("/path/to/cache.db", "/path/to/data.db");
 /// ```
 ///
 /// [`init_blocks_table`]: crate::init::init_blocks_table
 pub fn scan_cached_blocks<P: AsRef<Path>, Q: AsRef<Path>>(
    db_cache: P,
    db_data: Q,
 ) -> Result<(), Error> {
    let cache = Connection::open(db_cache)?;
    let data = Connection::open(db_data)?;
    // Recall where we synced up to previously.
    // If we have never synced, use sapling activation height to select all cached CompactBlocks.
    let mut last_height = data.query_row("SELECT MAX(height) FROM blocks", NO_PARAMS, |row| {
        row.get(0).or(Ok(SAPLING_ACTIVATION_HEIGHT - 1))
    })?;
    // Fetch the CompactBlocks we need to scan
    let mut stmt_blocks = cache
        .prepare("SELECT height, data FROM compactblocks WHERE height > ? ORDER BY height ASC")?;
    let rows = stmt_blocks.query_map(&[last_height], |row| {
        Ok(CompactBlockRow {
            height: row.get(0)?,
            data: row.get(1)?,
        })
    })?;
    // Fetch the ExtendedFullViewingKeys we are tracking
    let mut stmt_fetch_accounts =
        data.prepare("SELECT extfvk FROM accounts ORDER BY account ASC")?;
    let extfvks = stmt_fetch_accounts.query_map(NO_PARAMS, |row| {
        row.get(0).map(|extfvk: String| {
            decode_extended_full_viewing_key(HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY, &extfvk)
        })
    })?;
    // Raise SQL errors from the query, IO errors from parsing, and incorrect HRP errors.
    let extfvks: Vec<_> = extfvks
        .collect::<Result<Result<Option<_>, _>, _>>()??
        .ok_or(Error(ErrorKind::IncorrectHRPExtFVK))?;
    // Get the most recent CommitmentTree
    let mut stmt_fetch_tree = data.prepare("SELECT sapling_tree FROM blocks WHERE height = ?")?;
    let mut tree = stmt_fetch_tree
        .query_row(&[last_height], |row| {
            row.get(0).map(|data: Vec<_>| {
                CommitmentTree::read(&data[..]).unwrap_or_else(|_| CommitmentTree::new())
            })
        })
        .unwrap_or_else(|_| CommitmentTree::new());
    // Get most recent incremental witnesses for the notes we are tracking
    let mut stmt_fetch_witnesses =
        data.prepare("SELECT note, witness FROM sapling_witnesses WHERE block = ?")?;
    let witnesses = stmt_fetch_witnesses.query_map(&[last_height], |row| {
        let id_note = row.get(0)?;
        let data: Vec<_> = row.get(1)?;
        Ok(IncrementalWitness::read(&data[..]).map(|witness| WitnessRow { id_note, witness }))
    })?;
    let mut witnesses: Vec<_> = witnesses.collect::<Result<Result<_, _>, _>>()??;
    // Get the nullifiers for the notes we are tracking
    let mut stmt_fetch_nullifiers =
        data.prepare("SELECT id_note, nf, account FROM received_notes WHERE spent IS NULL")?;
    let nullifiers = stmt_fetch_nullifiers.query_map(NO_PARAMS, |row| {
        let nf: Vec<_> = row.get(1)?;
        let account: i64 = row.get(2)?;
        Ok((nf, account as usize))
    })?;
    let mut nullifiers: Vec<_> = nullifiers.collect::<Result<_, _>>()?;
    // Prepare per-block SQL statements
    let mut stmt_insert_block = data.prepare(
        "INSERT INTO blocks (height, hash, time, sapling_tree)
        VALUES (?, ?, ?, ?)",
    )?;
    let mut stmt_update_tx = data.prepare(
        "UPDATE transactions
        SET block = ?, tx_index = ? WHERE txid = ?",
    )?;
    let mut stmt_insert_tx = data.prepare(
        "INSERT INTO transactions (txid, block, tx_index)
        VALUES (?, ?, ?)",
    )?;
    let mut stmt_select_tx = data.prepare("SELECT id_tx FROM transactions WHERE txid = ?")?;
    let mut stmt_mark_spent_note =
        data.prepare("UPDATE received_notes SET spent = ? WHERE nf = ?")?;
    let mut stmt_insert_note = data.prepare(
        "INSERT INTO received_notes (tx, output_index, account, diversifier, value, rcm, nf, is_change)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
    )?;
    let mut stmt_insert_witness = data.prepare(
        "INSERT INTO sapling_witnesses (note, block, witness)
        VALUES (?, ?, ?)",
    )?;
    let mut stmt_prune_witnesses = data.prepare("DELETE FROM sapling_witnesses WHERE block < ?")?;
    let mut stmt_update_expired = data.prepare(
        "UPDATE received_notes SET spent = NULL WHERE EXISTS (
            SELECT id_tx FROM transactions
            WHERE id_tx = received_notes.spent AND block IS NULL AND expiry_height < ?
        )",
    )?;
    for row in rows {
        let row = row?;
        // Start an SQL transaction for this block.
        data.execute("BEGIN IMMEDIATE", NO_PARAMS)?;
        // Scanned blocks MUST be height-sequential.
        if row.height != (last_height + 1) {
            return Err(Error(ErrorKind::InvalidHeight(last_height + 1, row.height)));
        }
        last_height = row.height;
        let block: CompactBlock = parse_from_bytes(&row.data)?;
        let block_hash = block.hash.clone();
        let block_time = block.time;
        let txs = {
            let nf_refs: Vec<_> = nullifiers.iter().map(|(nf, acc)| (&nf[..], *acc)).collect();
            let mut witness_refs: Vec<_> = witnesses.iter_mut().map(|w| &mut w.witness).collect();
            scan_block(
                block,
                &extfvks[..],
                &nf_refs,
                &mut tree,
                &mut witness_refs[..],
            )
        };
        // Enforce that all roots match. This is slow, so only include in debug builds.
        #[cfg(debug_assertions)]
        {
            let cur_root = tree.root();
            for row in &witnesses {
                if row.witness.root() != cur_root {
                    return Err(Error(ErrorKind::InvalidWitnessAnchor(
                        row.id_note,
                        last_height,
                    )));
                }
            }
            for tx in &txs {
                for output in tx.shielded_outputs.iter() {
                    if output.witness.root() != cur_root {
                        return Err(Error(ErrorKind::InvalidNewWitnessAnchor(
                            output.index,
                            tx.txid,
                            last_height,
                            output.witness.root(),
                        )));
                    }
                }
            }
        }
        // Insert the block into the database.
        let mut encoded_tree = Vec::new();
        tree.write(&mut encoded_tree)
            .expect("Should be able to write to a Vec");
        stmt_insert_block.execute(&[
            row.height.to_sql()?,
            block_hash.to_sql()?,
            block_time.to_sql()?,
            encoded_tree.to_sql()?,
        ])?;
        for tx in txs {
            // First try update an existing transaction in the database.
            let txid = tx.txid.0.to_vec();
            let tx_row = if stmt_update_tx.execute(&[
                row.height.to_sql()?,
                (tx.index as i64).to_sql()?,
                txid.to_sql()?,
            ])? == 0
            {
                // It isn't there, so insert our transaction into the database.
                stmt_insert_tx.execute(&[
                    txid.to_sql()?,
                    row.height.to_sql()?,
                    (tx.index as i64).to_sql()?,
                ])?;
                data.last_insert_rowid()
            } else {
                // It was there, so grab its row number.
                stmt_select_tx.query_row(&[txid], |row| row.get(0))?
            };
            // Mark notes as spent and remove them from the scanning cache
            for spend in &tx.shielded_spends {
                stmt_mark_spent_note.execute(&[tx_row.to_sql()?, spend.nf.to_sql()?])?;
            }
            nullifiers = nullifiers
                .into_iter()
                .filter(|(nf, _acc)| {
                    tx.shielded_spends
                        .iter()
                        .find(|spend| &spend.nf == nf)
                        .is_none()
                })
                .collect();
            for output in tx.shielded_outputs {
                let mut rcm = [0; 32];
                output.note.r.into_repr().write_le(&mut rcm[..])?;
                let nf = output.note.nf(
                    &extfvks[output.account].fvk.vk,
                    output.witness.position() as u64,
                    &JUBJUB,
                );
                // Insert received note into the database.
                // Assumptions:
                // - A transaction will not contain more than 2^63 shielded outputs.
                // - A note value will never exceed 2^63 zatoshis.
                stmt_insert_note.execute(&[
                    tx_row.to_sql()?,
                    (output.index as i64).to_sql()?,
                    (output.account as i64).to_sql()?,
                    output.to.diversifier.0.to_sql()?,
                    (output.note.value as i64).to_sql()?,
                    rcm.to_sql()?,
                    nf.to_sql()?,
                    output.is_change.to_sql()?,
                ])?;
                let note_row = data.last_insert_rowid();
                // Save witness for note.
                witnesses.push(WitnessRow {
                    id_note: note_row,
                    witness: output.witness,
                });
                // Cache nullifier for note (to detect subsequent spends in this scan).
                nullifiers.push((nf, output.account));
            }
        }
        // Insert current witnesses into the database.
        let mut encoded = Vec::new();
        for witness_row in witnesses.iter() {
            encoded.clear();
            witness_row
                .witness
                .write(&mut encoded)
                .expect("Should be able to write to a Vec");
            stmt_insert_witness.execute(&[
                witness_row.id_note.to_sql()?,
                last_height.to_sql()?,
                encoded.to_sql()?,
            ])?;
        }
        // Prune the stored witnesses (we only expect rollbacks of at most 100 blocks).
        stmt_prune_witnesses.execute(&[last_height - 100])?;
        // Update now-expired transactions that didn't get mined.
        stmt_update_expired.execute(&[last_height])?;
        // Commit the SQL transaction, writing this block's data atomically.
        data.execute("COMMIT", NO_PARAMS)?;
    }
    Ok(())
 }
 #[cfg(test)]
 mod tests {
    use tempfile::NamedTempFile;
    use zcash_primitives::{
        block::BlockHash,
        transaction::components::Amount,
        zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    };
    use super::scan_cached_blocks;
    use crate::{
        init::{init_accounts_table, init_cache_database, init_data_database},
        query::get_balance,
        tests::{fake_compact_block, fake_compact_block_spending, insert_into_cache},
        SAPLING_ACTIVATION_HEIGHT,
    };
    #[test]
    fn scan_cached_blocks_requires_sequential_blocks() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Create a block with height SAPLING_ACTIVATION_HEIGHT
        let value = Amount::from_u64(50000).unwrap();
        let (cb1, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb1);
        scan_cached_blocks(db_cache, db_data).unwrap();
        assert_eq!(get_balance(db_data, 0).unwrap(), value);
        // We cannot scan a block of height SAPLING_ACTIVATION_HEIGHT + 2 next
        let (cb2, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 1,
            cb1.hash(),
            extfvk.clone(),
            value,
        );
        let (cb3, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 2,
            cb2.hash(),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb3);
        match scan_cached_blocks(db_cache, db_data) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(
                e.to_string(),
                format!(
                    "Expected height of next CompactBlock to be {}, but was {}",
                    SAPLING_ACTIVATION_HEIGHT + 1,
                    SAPLING_ACTIVATION_HEIGHT + 2
                )
            ),
        }
        // If we add a block of height SAPLING_ACTIVATION_HEIGHT + 1, we can now scan both
        insert_into_cache(db_cache, &cb2);
        scan_cached_blocks(db_cache, db_data).unwrap();
        assert_eq!(
            get_balance(db_data, 0).unwrap(),
            Amount::from_u64(150_000).unwrap()
        );
    }
    #[test]
    fn scan_cached_blocks_finds_received_notes() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Account balance should be zero
        assert_eq!(get_balance(db_data, 0).unwrap(), Amount::zero());
        // Create a fake CompactBlock sending value to the address
        let value = Amount::from_u64(5).unwrap();
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb);
        // Scan the cache
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Account balance should reflect the received note
        assert_eq!(get_balance(db_data, 0).unwrap(), value);
        // Create a second fake CompactBlock sending more value to the address
        let value2 = Amount::from_u64(7).unwrap();
        let (cb2, _) = fake_compact_block(SAPLING_ACTIVATION_HEIGHT + 1, cb.hash(), extfvk, value2);
        insert_into_cache(db_cache, &cb2);
        // Scan the cache again
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Account balance should reflect both received notes
        assert_eq!(get_balance(db_data, 0).unwrap(), value + value2);
    }
    #[test]
    fn scan_cached_blocks_finds_change_notes() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Account balance should be zero
        assert_eq!(get_balance(db_data, 0).unwrap(), Amount::zero());
        // Create a fake CompactBlock sending value to the address
        let value = Amount::from_u64(5).unwrap();
        let (cb, nf) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb);
        // Scan the cache
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Account balance should reflect the received note
        assert_eq!(get_balance(db_data, 0).unwrap(), value);
        // Create a second fake CompactBlock spending value from the address
        let extsk2 = ExtendedSpendingKey::master(&[0]);
        let to2 = extsk2.default_address().unwrap().1;
        let value2 = Amount::from_u64(2).unwrap();
        insert_into_cache(
            db_cache,
            &fake_compact_block_spending(
                SAPLING_ACTIVATION_HEIGHT + 1,
                cb.hash(),
                (nf, value),
                extfvk,
                to2,
                value2,
            ),
        );
        // Scan the cache again
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Account balance should equal the change
        assert_eq!(get_balance(db_data, 0).unwrap(), value - value2);
    }
 }
--- a/zcash_client_sqlite/src/transact.rs
+++ b/zcash_client_sqlite/src/transact.rs
@@ -1,665 +0,0 @@
 //! Functions for creating transactions.
 use ff::{PrimeField, PrimeFieldRepr};
 use pairing::bls12_381::Bls12;
 use rusqlite::{types::ToSql, Connection, NO_PARAMS};
 use std::path::Path;
 use zcash_client_backend::encoding::encode_extended_full_viewing_key;
 use zcash_primitives::{
    jubjub::fs::{Fs, FsRepr},
    merkle_tree::IncrementalWitness,
    note_encryption::Memo,
    primitives::{Diversifier, Note},
    prover::TxProver,
    sapling::Node,
    transaction::{
        builder::Builder,
        components::{amount::DEFAULT_FEE, Amount},
    },
    zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    JUBJUB,
 };
 use crate::{
    address::RecipientAddress,
    error::{Error, ErrorKind},
    get_target_and_anchor_heights, HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
 };
 struct SelectedNoteRow {
    diversifier: Diversifier,
    note: Note<Bls12>,
    witness: IncrementalWitness<Node>,
 }
 /// Creates a transaction paying the specified address from the given account.
 ///
 /// Returns the row index of the newly-created transaction in the `transactions` table
 /// within the data database. The caller can read the raw transaction bytes from the `raw`
 /// column in order to broadcast the transaction to the network.
 ///
 /// Do not call this multiple times in parallel, or you will generate transactions that
 /// double-spend the same notes.
 ///
 /// # Examples
 ///
 /// ```
 /// use zcash_client_backend::{
 ///     constants::{testnet::COIN_TYPE, SAPLING_CONSENSUS_BRANCH_ID},
 ///     keys::spending_key,
 /// };
 /// use zcash_client_sqlite::transact::create_to_address;
 /// use zcash_primitives::transaction::components::Amount;
 /// use zcash_proofs::prover::LocalTxProver;
 ///
 /// let tx_prover = match LocalTxProver::with_default_location() {
 ///     Some(tx_prover) => tx_prover,
 ///     None => {
 ///         panic!("Cannot locate the Zcash parameters. Please run zcash-fetch-params or fetch-params.sh to download the parameters, and then re-run the tests.");
 ///     }
 /// };
 ///
 /// let account = 0;
 /// let extsk = spending_key(&[0; 32][..], COIN_TYPE, account);
 /// let to = extsk.default_address().unwrap().1.into();
 /// match create_to_address(
 ///     "/path/to/data.db",
 ///     SAPLING_CONSENSUS_BRANCH_ID,
 ///     tx_prover,
 ///     (account, &extsk),
 ///     &to,
 ///     Amount::from_u64(1).unwrap(),
 ///     None,
 /// ) {
 ///     Ok(tx_row) => (),
 ///     Err(e) => (),
 /// }
 /// ```
 pub fn create_to_address<P: AsRef<Path>>(
    db_data: P,
    consensus_branch_id: u32,
    prover: impl TxProver,
    (account, extsk): (u32, &ExtendedSpendingKey),
    to: &RecipientAddress,
    value: Amount,
    memo: Option<Memo>,
 ) -> Result<i64, Error> {
    let data = Connection::open(db_data)?;
    // Check that the ExtendedSpendingKey we have been given corresponds to the
    // ExtendedFullViewingKey for the account we are spending from.
    let extfvk = ExtendedFullViewingKey::from(extsk);
    if !data
        .prepare("SELECT * FROM accounts WHERE account = ? AND extfvk = ?")?
        .exists(&[
            account.to_sql()?,
            encode_extended_full_viewing_key(HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY, &extfvk)
                .to_sql()?,
        ])?
    {
        return Err(Error(ErrorKind::InvalidExtSK(account)));
    }
    let ovk = extfvk.fvk.ovk;
    // Target the next block, assuming we are up-to-date.
    let (height, anchor_height) = {
        let (target_height, anchor_height) = get_target_and_anchor_heights(&data)?;
        (target_height, i64::from(anchor_height))
    };
    // The goal of this SQL statement is to select the oldest notes until the required
    // value has been reached, and then fetch the witnesses at the desired height for the
    // selected notes. This is achieved in several steps:
    //
    // 1) Use a window function to create a view of all notes, ordered from oldest to
    //    newest, with an additional column containing a running sum:
    //    - Unspent notes accumulate the values of all unspent notes in that note's
    //      account, up to itself.
    //    - Spent notes accumulate the values of all notes in the transaction they were
    //      spent in, up to itself.
    //
    // 2) Select all unspent notes in the desired account, along with their running sum.
    //
    // 3) Select all notes for which the running sum was less than the required value, as
    //    well as a single note for which the sum was greater than or equal to the
    //    required value, bringing the sum of all selected notes across the threshold.
    //
    // 4) Match the selected notes against the witnesses at the desired height.
    let target_value = i64::from(value + DEFAULT_FEE);
    let mut stmt_select_notes = data.prepare(
        "WITH selected AS (
            WITH eligible AS (
                SELECT id_note, diversifier, value, rcm,
                    SUM(value) OVER
                        (PARTITION BY account, spent ORDER BY id_note) AS so_far
                FROM received_notes
                INNER JOIN transactions ON transactions.id_tx = received_notes.tx
                WHERE account = ? AND spent IS NULL AND transactions.block <= ?
            )
            SELECT * FROM eligible WHERE so_far < ?
            UNION
            SELECT * FROM (SELECT * FROM eligible WHERE so_far >= ? LIMIT 1)
        ), witnesses AS (
            SELECT note, witness FROM sapling_witnesses
            WHERE block = ?
        )
        SELECT selected.diversifier, selected.value, selected.rcm, witnesses.witness
        FROM selected
        INNER JOIN witnesses ON selected.id_note = witnesses.note",
    )?;
    // Select notes
    let notes = stmt_select_notes.query_and_then::<_, Error, _, _>(
        &[
            i64::from(account),
            anchor_height,
            target_value,
            target_value,
            anchor_height,
        ],
        |row| {
            let diversifier = {
                let d: Vec<_> = row.get(0)?;
                if d.len() != 11 {
                    return Err(Error(ErrorKind::CorruptedData(
                        "Invalid diversifier length",
                    )));
                }
                let mut tmp = [0; 11];
                tmp.copy_from_slice(&d);
                Diversifier(tmp)
            };
            let note_value: i64 = row.get(1)?;
            let rcm = {
                let d: Vec<_> = row.get(2)?;
                let mut tmp = FsRepr::default();
                tmp.read_le(&d[..])?;
                Fs::from_repr(tmp).map_err(|_| Error(ErrorKind::InvalidNote))?
            };
            let from = extfvk
                .fvk
                .vk
                .into_payment_address(diversifier, &JUBJUB)
                .unwrap();
            let note = from.create_note(note_value as u64, rcm, &JUBJUB).unwrap();
            let witness = {
                let d: Vec<_> = row.get(3)?;
                IncrementalWitness::read(&d[..])?
            };
            Ok(SelectedNoteRow {
                diversifier,
                note,
                witness,
            })
        },
    )?;
    let notes: Vec<SelectedNoteRow> = notes.collect::<Result<_, _>>()?;
    // Confirm we were able to select sufficient value
    let selected_value = notes
        .iter()
        .fold(0, |acc, selected| acc + selected.note.value);
    if selected_value < target_value as u64 {
        return Err(Error(ErrorKind::InsufficientBalance(
            selected_value,
            target_value as u64,
        )));
    }
    // Create the transaction
    let mut builder = Builder::new(height);
    for selected in notes {
        builder.add_sapling_spend(
            extsk.clone(),
            selected.diversifier,
            selected.note,
            selected.witness,
        )?;
    }
    match to {
        RecipientAddress::Shielded(to) => {
            builder.add_sapling_output(ovk, to.clone(), value, memo.clone())
        }
        RecipientAddress::Transparent(to) => builder.add_transparent_output(&to, value),
    }?;
    let (tx, tx_metadata) = builder.build(consensus_branch_id, prover)?;
    // We only called add_sapling_output() once.
    let output_index = match tx_metadata.output_index(0) {
        Some(idx) => idx as i64,
        None => panic!("Output 0 should exist in the transaction"),
    };
    let created = time::get_time();
    // Update the database atomically, to ensure the result is internally consistent.
    data.execute("BEGIN IMMEDIATE", NO_PARAMS)?;
    // Save the transaction in the database.
    let mut raw_tx = vec![];
    tx.write(&mut raw_tx)?;
    let mut stmt_insert_tx = data.prepare(
        "INSERT INTO transactions (txid, created, expiry_height, raw)
        VALUES (?, ?, ?, ?)",
    )?;
    stmt_insert_tx.execute(&[
        tx.txid().0.to_sql()?,
        created.to_sql()?,
        tx.expiry_height.to_sql()?,
        raw_tx.to_sql()?,
    ])?;
    let id_tx = data.last_insert_rowid();
    // Mark notes as spent.
    //
    // This locks the notes so they aren't selected again by a subsequent call to
    // create_to_address() before this transaction has been mined (at which point the notes
    // get re-marked as spent).
    //
    // Assumes that create_to_address() will never be called in parallel, which is a
    // reasonable assumption for a light client such as a mobile phone.
    let mut stmt_mark_spent_note =
        data.prepare("UPDATE received_notes SET spent = ? WHERE nf = ?")?;
    for spend in &tx.shielded_spends {
        stmt_mark_spent_note.execute(&[id_tx.to_sql()?, spend.nullifier.to_sql()?])?;
    }
    // Save the sent note in the database.
    // TODO: Decide how to save transparent output information.
    let to_str = to.to_string();
    if let Some(memo) = memo {
        let mut stmt_insert_sent_note = data.prepare(
            "INSERT INTO sent_notes (tx, output_index, from_account, address, value, memo)
            VALUES (?, ?, ?, ?, ?, ?)",
        )?;
        stmt_insert_sent_note.execute(&[
            id_tx.to_sql()?,
            output_index.to_sql()?,
            account.to_sql()?,
            to_str.to_sql()?,
            i64::from(value).to_sql()?,
            memo.as_bytes().to_sql()?,
        ])?;
    } else {
        let mut stmt_insert_sent_note = data.prepare(
            "INSERT INTO sent_notes (tx, output_index, from_account, address, value)
            VALUES (?, ?, ?, ?, ?)",
        )?;
        stmt_insert_sent_note.execute(&[
            id_tx.to_sql()?,
            output_index.to_sql()?,
            account.to_sql()?,
            to_str.to_sql()?,
            i64::from(value).to_sql()?,
        ])?;
    }
    data.execute("COMMIT", NO_PARAMS)?;
    // Return the row number of the transaction, so the caller can fetch it for sending.
    Ok(id_tx)
 }
 #[cfg(test)]
 mod tests {
    use tempfile::NamedTempFile;
    use zcash_primitives::{
        block::BlockHash,
        prover::TxProver,
        transaction::components::Amount,
        zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    };
    use zcash_proofs::prover::LocalTxProver;
    use super::create_to_address;
    use crate::{
        init::{init_accounts_table, init_blocks_table, init_cache_database, init_data_database},
        query::{get_balance, get_verified_balance},
        scan::scan_cached_blocks,
        tests::{fake_compact_block, insert_into_cache},
        SAPLING_ACTIVATION_HEIGHT,
    };
    fn test_prover() -> impl TxProver {
        match LocalTxProver::with_default_location() {
            Some(tx_prover) => tx_prover,
            None => {
                panic!("Cannot locate the Zcash parameters. Please run zcash-fetch-params or fetch-params.sh to download the parameters, and then re-run the tests.");
            }
        }
    }
    #[test]
    fn create_to_address_fails_on_incorrect_extsk() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add two accounts to the wallet
        let extsk0 = ExtendedSpendingKey::master(&[]);
        let extsk1 = ExtendedSpendingKey::master(&[0]);
        let extfvks = [
            ExtendedFullViewingKey::from(&extsk0),
            ExtendedFullViewingKey::from(&extsk1),
        ];
        init_accounts_table(&db_data, &extfvks).unwrap();
        let to = extsk0.default_address().unwrap().1.into();
        // Invalid extsk for the given account should cause an error
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk1),
            &to,
            Amount::from_u64(1).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(e.to_string(), "Incorrect ExtendedSpendingKey for account 0"),
        }
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (1, &extsk0),
            &to,
            Amount::from_u64(1).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(e.to_string(), "Incorrect ExtendedSpendingKey for account 1"),
        }
    }
    #[test]
    fn create_to_address_fails_with_no_blocks() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvks = [ExtendedFullViewingKey::from(&extsk)];
        init_accounts_table(&db_data, &extfvks).unwrap();
        let to = extsk.default_address().unwrap().1.into();
        // We cannot do anything if we aren't synchronised
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(1).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(e.to_string(), "Must scan blocks first"),
        }
    }
    #[test]
    fn create_to_address_fails_on_insufficient_balance() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        init_blocks_table(&db_data, 1, BlockHash([1; 32]), 1, &[]).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvks = [ExtendedFullViewingKey::from(&extsk)];
        init_accounts_table(&db_data, &extfvks).unwrap();
        let to = extsk.default_address().unwrap().1.into();
        // Account balance should be zero
        assert_eq!(get_balance(db_data, 0).unwrap(), Amount::zero());
        // We cannot spend anything
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(1).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(
                e.to_string(),
                "Insufficient balance (have 0, need 10001 including fee)"
            ),
        }
    }
    #[test]
    fn create_to_address_fails_on_unverified_notes() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Add funds to the wallet in a single note
        let value = Amount::from_u64(50000).unwrap();
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb);
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Verified balance matches total balance
        assert_eq!(get_balance(db_data, 0).unwrap(), value);
        assert_eq!(get_verified_balance(db_data, 0).unwrap(), value);
        // Add more funds to the wallet in a second note
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 1,
            cb.hash(),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb);
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Verified balance does not include the second note
        assert_eq!(get_balance(db_data, 0).unwrap(), value + value);
        assert_eq!(get_verified_balance(db_data, 0).unwrap(), value);
        // Spend fails because there are insufficient verified notes
        let extsk2 = ExtendedSpendingKey::master(&[]);
        let to = extsk2.default_address().unwrap().1.into();
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(70000).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(
                e.to_string(),
                "Insufficient balance (have 50000, need 80000 including fee)"
            ),
        }
        // Mine blocks SAPLING_ACTIVATION_HEIGHT + 2 to 9 until just before the second
        // note is verified
        for i in 2..10 {
            let (cb, _) = fake_compact_block(
                SAPLING_ACTIVATION_HEIGHT + i,
                cb.hash(),
                extfvk.clone(),
                value,
            );
            insert_into_cache(db_cache, &cb);
        }
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Second spend still fails
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(70000).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(
                e.to_string(),
                "Insufficient balance (have 50000, need 80000 including fee)"
            ),
        }
        // Mine block 11 so that the second note becomes verified
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 10,
            cb.hash(),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb);
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Second spend should now succeed
        create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(70000).unwrap(),
            None,
        )
        .unwrap();
    }
    #[test]
    fn create_to_address_fails_on_locked_notes() {
        let cache_file = NamedTempFile::new().unwrap();
        let db_cache = cache_file.path();
        init_cache_database(&db_cache).unwrap();
        let data_file = NamedTempFile::new().unwrap();
        let db_data = data_file.path();
        init_data_database(&db_data).unwrap();
        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvk = ExtendedFullViewingKey::from(&extsk);
        init_accounts_table(&db_data, &[extfvk.clone()]).unwrap();
        // Add funds to the wallet in a single note
        let value = Amount::from_u64(50000).unwrap();
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT,
            BlockHash([0; 32]),
            extfvk.clone(),
            value,
        );
        insert_into_cache(db_cache, &cb);
        scan_cached_blocks(db_cache, db_data).unwrap();
        assert_eq!(get_balance(db_data, 0).unwrap(), value);
        // Send some of the funds to another address
        let extsk2 = ExtendedSpendingKey::master(&[]);
        let to = extsk2.default_address().unwrap().1.into();
        create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(15000).unwrap(),
            None,
        )
        .unwrap();
        // A second spend fails because there are no usable notes
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(2000).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(
                e.to_string(),
                "Insufficient balance (have 0, need 12000 including fee)"
            ),
        }
        // Mine blocks SAPLING_ACTIVATION_HEIGHT + 1 to 21 (that don't send us funds)
        // until just before the first transaction expires
        for i in 1..22 {
            let (cb, _) = fake_compact_block(
                SAPLING_ACTIVATION_HEIGHT + i,
                cb.hash(),
                ExtendedFullViewingKey::from(&ExtendedSpendingKey::master(&[i as u8])),
                value,
            );
            insert_into_cache(db_cache, &cb);
        }
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Second spend still fails
        match create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(2000).unwrap(),
            None,
        ) {
            Ok(_) => panic!("Should have failed"),
            Err(e) => assert_eq!(
                e.to_string(),
                "Insufficient balance (have 0, need 12000 including fee)"
            ),
        }
        // Mine block SAPLING_ACTIVATION_HEIGHT + 22 so that the first transaction expires
        let (cb, _) = fake_compact_block(
            SAPLING_ACTIVATION_HEIGHT + 22,
            cb.hash(),
            ExtendedFullViewingKey::from(&ExtendedSpendingKey::master(&[22])),
            value,
        );
        insert_into_cache(db_cache, &cb);
        scan_cached_blocks(db_cache, db_data).unwrap();
        // Second spend should now succeed
        create_to_address(
            db_data,
            1,
            test_prover(),
            (0, &extsk),
            &to,
            Amount::from_u64(2000).unwrap(),
            None,
        )
        .unwrap();
    }
 }
--- a/zcash_history/.gitignore
+++ b/zcash_history/.gitignore
@@ -0,0 +1,4 @@
 /target
 **/*.rs.bk
 Cargo.lock
 .idea
--- a/zcash_history/COPYRIGHT
+++ b/zcash_history/COPYRIGHT
@@ -0,0 +1,14 @@
 Copyrights in the "zcash_history" library are retained by their contributors. No
 copyright assignment is required to contribute to the "zcash_history" library.
 The "zcash_history" library is licensed under either of
 * Apache License, Version 2.0, (see ./LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license (see ./LICENSE-MIT or http://opensource.org/licenses/MIT)
 at your option.
 Unless you explicitly state otherwise, any contribution intentionally
 submitted for inclusion in the work by you, as defined in the Apache-2.0
 license, shall be dual licensed as above, without any additional terms or
 conditions.
--- a/zcash_history/Cargo.toml
+++ b/zcash_history/Cargo.toml
@@ -0,0 +1,17 @@
 [package]
 name = "zcash_history"
 version = "0.0.1"
 authors = ["NikVolf <nikvolf@gmail.com>"]
 edition = "2018"
 license = "MIT/Apache-2.0"
 documentation = "https://docs.rs/zcash_history/"
 description = "Library for Zcash blockchain history tools"
 [dev-dependencies]
 assert_matches = "1.3.0"
 quickcheck = "0.8"
 [dependencies]
 bigint = "4"
 byteorder = "1"
 blake2 = { package = "blake2b_simd", version = "0.5" }
--- a/zcash_history/LICENSE-APACHE
+++ b/zcash_history/LICENSE-APACHE
@@ -0,0 +1,201 @@
                              Apache License
                        Version 2.0, January 2004
                     http://www.apache.org/licenses/
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--- a/zcash_history/LICENSE-MIT
+++ b/zcash_history/LICENSE-MIT
@@ -0,0 +1,25 @@
 Copyright (c) 2019 Nikolay Volf
 Permission is hereby granted, free of charge, to any
 person obtaining a copy of this software and associated
 documentation files (the "Software"), to deal in the
 Software without restriction, including without
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 conditions:
 The above copyright notice and this permission notice
 shall be included in all copies or substantial portions
 of the Software.
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
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 TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
 SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
 IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.
--- a/zcash_history/README.md
+++ b/zcash_history/README.md
@@ -0,0 +1,26 @@
 # zcash_history
 Special implementation of Merkle mountain ranges (MMR) for Zcash!
 [![Build Status](https://travis-ci.org/NikVolf/zcash-mmr.svg?branch=master)](https://travis-ci.org/NikVolf/zcash-mmr)
 The main design goals of this MMR implementation are
 - Allow zero-cache and avoid db callbacks. As it is implemented, calling side must just smartly pre-load MMR nodes from the database (about log2(tree length) for append, twice as much for deletion).
 - Reuse as much logic between rust and c++ clients and place it here and librustzcash.
 - Close to zero memory consumption.
 # License
 `zcash_history` is distributed under the terms of both the MIT
 license and the Apache License (Version 2.0), at your choice.
 See LICENSE-APACHE, and LICENSE-MIT for details.
 ### Contribution
 Unless you explicitly state otherwise, any contribution intentionally submitted
 for inclusion in `zcash_history` by you, as defined in the Apache-2.0 license, shall be
 dual licensed as above, without any additional terms or conditions.
--- a/zcash_history/examples/lib/main.rs
+++ b/zcash_history/examples/lib/main.rs
@@ -0,0 +1,2 @@
 // dummy example
 pub fn main() {}
--- a/zcash_history/examples/lib/shared.rs
+++ b/zcash_history/examples/lib/shared.rs
@@ -0,0 +1,86 @@
 use zcash_history::{Entry, EntryLink, NodeData, Tree};
 pub struct NodeDataIterator {
    return_stack: Vec<NodeData>,
    tree: Tree,
    cursor: usize,
    leaf_cursor: usize,
 }
 impl Iterator for NodeDataIterator {
    type Item = NodeData;
    fn next(&mut self) -> Option<NodeData> {
        let result = if self.cursor == 1 {
            self.leaf_cursor = 2;
            Some(leaf(1))
        } else if self.cursor == 2 {
            self.leaf_cursor = 3;
            Some(leaf(2))
        } else if self.cursor == 3 {
            Some(self.tree.root_node().expect("always exists").data().clone())
        } else if self.return_stack.len() > 0 {
            self.return_stack.pop()
        } else {
            for n_append in self
                .tree
                .append_leaf(leaf(self.leaf_cursor as u32))
                .expect("full tree cannot fail")
                .into_iter()
                .rev()
            {
                self.return_stack.push(
                    self.tree
                        .resolve_link(n_append)
                        .expect("just pushed")
                        .data()
                        .clone(),
                )
            }
            self.leaf_cursor += 1;
            self.return_stack.pop()
        };
        self.cursor += 1;
        result
    }
 }
 impl NodeDataIterator {
    pub fn new() -> Self {
        let root = Entry::new(
            NodeData::combine(&leaf(1), &leaf(2)),
            EntryLink::Stored(0),
            EntryLink::Stored(1),
        );
        let tree = Tree::new(
            3,
            vec![(2, root)],
            vec![(0, leaf(1).into()), (1, leaf(2).into())],
        );
        NodeDataIterator {
            return_stack: Vec::new(),
            tree,
            cursor: 1,
            leaf_cursor: 1,
        }
    }
 }
 fn leaf(height: u32) -> NodeData {
    NodeData {
        consensus_branch_id: 0,
        subtree_commitment: [0u8; 32],
        start_time: height * 10 + 1,
        end_time: (height + 1) * 10,
        start_target: 100 + height * 10,
        end_target: 100 + (height + 1) * 10,
        start_sapling_root: [0u8; 32],
        end_sapling_root: [0u8; 32],
        subtree_total_work: 0.into(),
        start_height: height as u64,
        end_height: height as u64,
        sapling_tx: 5 + height as u64,
    }
 }
--- a/zcash_history/examples/long.rs
+++ b/zcash_history/examples/long.rs
@@ -0,0 +1,113 @@
 use zcash_history::{Entry, EntryLink, NodeData, Tree};
 #[path = "lib/shared.rs"]
 mod share;
 fn draft(into: &mut Vec<(u32, Entry)>, vec: &Vec<NodeData>, peak_pos: usize, h: u32) {
    let node_data = vec[peak_pos - 1].clone();
    let peak: Entry = match h {
        0 => node_data.into(),
        _ => Entry::new(
            node_data,
            EntryLink::Stored((peak_pos - (1 << h) - 1) as u32),
            EntryLink::Stored((peak_pos - 2) as u32),
        ),
    };
    println!("Entry #{}: {}", into.len(), peak);
    into.push(((peak_pos - 1) as u32, peak));
 }
 fn prepare_tree(vec: &Vec<NodeData>) -> Tree {
    assert!(vec.len() > 0);
    // integer log2 of (vec.len()+1), -1
    let mut h = (32 - ((vec.len() + 1) as u32).leading_zeros() - 1) - 1;
    let mut peak_pos = (1 << (h + 1)) - 1;
    let mut nodes = Vec::new();
    // used later
    let mut last_peak_pos = 0;
    let mut last_peak_h = 0;
    loop {
        if peak_pos > vec.len() {
            // left child, -2^h
            peak_pos = peak_pos - (1 << h);
            h = h - 1;
        }
        if peak_pos <= vec.len() {
            draft(&mut nodes, vec, peak_pos, h);
            // save to be used in next loop
            last_peak_pos = peak_pos;
            last_peak_h = h;
            // right sibling
            peak_pos = peak_pos + (1 << (h + 1)) - 1;
        }
        if h == 0 {
            break;
        }
    }
    // for deletion, everything on the right slope of the last peak should be pre-loaded
    let mut extra = Vec::new();
    let mut h = last_peak_h;
    let mut peak_pos = last_peak_pos;
    while h > 0 {
        let left_pos = peak_pos - (1 << h);
        let right_pos = peak_pos - 1;
        h = h - 1;
        // drafting left child
        draft(&mut extra, vec, left_pos, h);
        // drafting right child
        draft(&mut extra, vec, right_pos, h);
        // continuing on right slope
        peak_pos = right_pos;
    }
    println!("Total extra of {} required for deletion!", extra.len());
    Tree::new(vec.len() as u32, nodes, extra)
 }
 fn main() {
    let number = match std::env::args().skip(1).next() {
        None => {
            eprintln!("writer <number of nodes> [<out_file>]");
            std::process::exit(1);
        }
        Some(number) => number.parse::<usize>().expect("invalid number"),
    };
    let long_vec = share::NodeDataIterator::new()
        .take(number)
        .collect::<Vec<NodeData>>();
    let now = std::time::Instant::now();
    let tree = prepare_tree(&long_vec);
    let elapsed = now.elapsed();
    println!(
        "Tree final root: {}-{}",
        tree.root_node().expect("root").data().start_height,
        tree.root_node().expect("root").data().end_height,
    );
    println!(
        "Prepare tree of {} length: {} ns / {} mcs / {} ms",
        number,
        elapsed.as_nanos(),
        elapsed.as_micros(),
        elapsed.as_millis()
    );
 }
--- a/zcash_history/examples/write.rs
+++ b/zcash_history/examples/write.rs
@@ -0,0 +1,44 @@
 #[path = "lib/shared.rs"]
 mod share;
 // Test data generator
 // $ cargo run --example writer -- 16 nodes.dat
 // or
 // $ cargo run --example writer -- 16
 // to preview
 fn main() {
    let mut args = std::env::args().skip(1);
    let (number, out_file) = match args.next() {
        None => {
            eprintln!("writer <number of nodes> [<out_file>]");
            std::process::exit(1);
        }
        Some(number) => (
            number.parse::<usize>().expect("invalid number"),
            args.next(),
        ),
    };
    let iterator = share::NodeDataIterator::new().take(number);
    if let Some(out_file_path) = out_file {
        use std::io::Write;
        let mut buf = Vec::new();
        for node in iterator {
            node.write(&mut buf).expect("Failed to write data");
        }
        let mut file = std::fs::File::create(&out_file_path).expect("Failed to create output file");
        file.write_all(&buf[..])
            .expect("Failed to write data to file");
    } else {
        for n in iterator {
            println!("{:?}", n);
        }
    }
 }
--- a/zcash_history/src/entry.rs
+++ b/zcash_history/src/entry.rs
@@ -0,0 +1,123 @@
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use crate::{EntryKind, EntryLink, Error, NodeData, MAX_NODE_DATA_SIZE};
 /// Max serialized length of entry data.
 pub const MAX_ENTRY_SIZE: usize = MAX_NODE_DATA_SIZE + 9;
 /// MMR Entry.
 #[derive(Debug)]
 pub struct Entry {
    pub(crate) kind: EntryKind,
    pub(crate) data: NodeData,
 }
 impl Entry {
    /// New entry of type node.
    pub fn new(data: NodeData, left: EntryLink, right: EntryLink) -> Self {
        Entry {
            kind: EntryKind::Node(left, right),
            data,
        }
    }
    /// Returns if is this node complete (has total of 2^N leaves)
    pub fn complete(&self) -> bool {
        let leaves = self.leaf_count();
        leaves & (leaves - 1) == 0
    }
    /// Number of leaves under this node.
    pub fn leaf_count(&self) -> u64 {
        self.data.end_height - (self.data.start_height - 1)
    }
    /// Is this node a leaf.
    pub fn leaf(&self) -> bool {
        if let EntryKind::Leaf = self.kind {
            true
        } else {
            false
        }
    }
    /// Left child
    pub fn left(&self) -> Result<EntryLink, Error> {
        match self.kind {
            EntryKind::Leaf => Err(Error::node_expected()),
            EntryKind::Node(left, _) => Ok(left),
        }
    }
    /// Right child.
    pub fn right(&self) -> Result<EntryLink, Error> {
        match self.kind {
            EntryKind::Leaf => Err(Error::node_expected()),
            EntryKind::Node(_, right) => Ok(right),
        }
    }
    /// Read from byte representation.
    pub fn read<R: std::io::Read>(consensus_branch_id: u32, r: &mut R) -> std::io::Result<Self> {
        let kind = {
            match r.read_u8()? {
                0 => {
                    let left = r.read_u32::<LittleEndian>()?;
                    let right = r.read_u32::<LittleEndian>()?;
                    EntryKind::Node(EntryLink::Stored(left), EntryLink::Stored(right))
                }
                1 => EntryKind::Leaf,
                _ => return Err(std::io::Error::from(std::io::ErrorKind::InvalidData)),
            }
        };
        let data = NodeData::read(consensus_branch_id, r)?;
        Ok(Entry { kind, data })
    }
    /// Write to byte representation.
    pub fn write<W: std::io::Write>(&self, w: &mut W) -> std::io::Result<()> {
        match self.kind {
            EntryKind::Node(EntryLink::Stored(left), EntryLink::Stored(right)) => {
                w.write_u8(0)?;
                w.write_u32::<LittleEndian>(left)?;
                w.write_u32::<LittleEndian>(right)?;
            }
            EntryKind::Leaf => {
                w.write_u8(1)?;
            }
            _ => {
                return Err(std::io::Error::from(std::io::ErrorKind::InvalidData));
            }
        }
        self.data.write(w)?;
        Ok(())
    }
    /// Convert from byte representation.
    pub fn from_bytes<T: AsRef<[u8]>>(consensus_branch_id: u32, buf: T) -> std::io::Result<Self> {
        let mut cursor = std::io::Cursor::new(buf);
        Self::read(consensus_branch_id, &mut cursor)
    }
 }
 impl From<NodeData> for Entry {
    fn from(s: NodeData) -> Self {
        Entry {
            kind: EntryKind::Leaf,
            data: s,
        }
    }
 }
 impl std::fmt::Display for Entry {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self.kind {
            EntryKind::Node(l, r) => write!(f, "node({}, {}, ..)", l, r),
            EntryKind::Leaf => write!(f, "leaf(..)"),
        }
    }
 }
--- a/zcash_history/src/lib.rs
+++ b/zcash_history/src/lib.rs
@@ -0,0 +1,79 @@
 //! Chain history library for Zcash
 //!
 //! To be used in zebra and via FFI bindings in zcashd
 #![warn(missing_docs)]
 mod entry;
 mod node_data;
 mod tree;
 pub use entry::{Entry, MAX_ENTRY_SIZE};
 pub use node_data::{NodeData, MAX_NODE_DATA_SIZE};
 pub use tree::Tree;
 /// Crate-level error type
 #[derive(Debug)]
 pub enum Error {
    /// Entry expected to be presented in the tree view while it was not.
    ExpectedInMemory(EntryLink),
    /// Entry expected to be a node (specifying for which link this is not true).
    ExpectedNode(Option<EntryLink>),
 }
 impl std::fmt::Display for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match *self {
            Self::ExpectedInMemory(l) => write!(f, "Node/leaf expected to be in memory: {}", l),
            Self::ExpectedNode(None) => write!(f, "Node expected"),
            Self::ExpectedNode(Some(l)) => write!(f, "Node expected, not leaf: {}", l),
        }
    }
 }
 /// Reference to to the tree node.
 #[repr(C)]
 #[derive(Clone, Copy, Debug)]
 pub enum EntryLink {
    /// Reference to the stored (in the array representation) leaf/node.
    Stored(u32),
    /// Reference to the generated leaf/node.
    Generated(u32),
 }
 impl std::fmt::Display for EntryLink {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match *self {
            Self::Stored(v) => write!(f, "stored({})", v),
            Self::Generated(v) => write!(f, "generated({})", v),
        }
    }
 }
 /// MMR Node. It is leaf when `left`, `right` are `None` and node when they are not.
 #[repr(C)]
 #[derive(Debug)]
 pub enum EntryKind {
    /// Leaf entry.
    Leaf,
    /// Node entry with children links.
    Node(EntryLink, EntryLink),
 }
 impl Error {
    /// Entry expected to be a node (specifying for which link this is not true).
    pub fn link_node_expected(link: EntryLink) -> Self {
        Self::ExpectedNode(Some(link))
    }
    /// Some entry is expected to be node
    pub fn node_expected() -> Self {
        Self::ExpectedNode(None)
    }
    pub(crate) fn augment(self, link: EntryLink) -> Self {
        match self {
            Error::ExpectedNode(_) => Error::ExpectedNode(Some(link)),
            val => val,
        }
    }
 }
--- a/zcash_history/src/node_data.rs
+++ b/zcash_history/src/node_data.rs
@@ -0,0 +1,238 @@
 use bigint::U256;
 use blake2::Params as Blake2Params;
 use byteorder::{ByteOrder, LittleEndian, ReadBytesExt, WriteBytesExt};
 /// Maximum serialized size of the node metadata.
 pub const MAX_NODE_DATA_SIZE: usize = 32 + // subtree commitment
    4 +  // start time
    4 +  // end time
    4 +  // start target
    4 +  // end target
    32 + // start sapling tree root
    32 + // end sapling tree root
    32 + // subtree total work
    9 +  // start height (compact uint)
    9 +  // end height (compact uint)
    9; // Sapling tx count (compact uint)
       // = total of 171
 /// Node metadata.
 #[repr(C)]
 #[derive(Debug, Clone, Default)]
 #[cfg_attr(test, derive(PartialEq))]
 pub struct NodeData {
    /// Consensus branch id, should be provided by deserializing node.
    pub consensus_branch_id: u32,
    /// Subtree commitment - either block hash for leaves or hashsum of children for nodes.
    pub subtree_commitment: [u8; 32],
    /// Start time.
    pub start_time: u32,
    /// End time.
    pub end_time: u32,
    /// Start target.
    pub start_target: u32,
    /// End target.
    pub end_target: u32,
    /// Start sapling tree root.
    pub start_sapling_root: [u8; 32],
    /// End sapling tree root.
    pub end_sapling_root: [u8; 32],
    /// Part of tree total work.
    pub subtree_total_work: U256,
    /// Start height.
    pub start_height: u64,
    /// End height
    pub end_height: u64,
    /// Number of Sapling transactions.
    pub sapling_tx: u64,
 }
 fn blake2b_personal(personalization: &[u8], input: &[u8]) -> [u8; 32] {
    let hash_result = Blake2Params::new()
        .hash_length(32)
        .personal(personalization)
        .to_state()
        .update(input)
        .finalize();
    let mut result = [0u8; 32];
    result.copy_from_slice(hash_result.as_bytes());
    result
 }
 fn personalization(branch_id: u32) -> [u8; 16] {
    let mut result = [0u8; 16];
    result[..12].copy_from_slice(b"ZcashHistory");
    LittleEndian::write_u32(&mut result[12..], branch_id);
    result
 }
 impl NodeData {
    /// Combine two nodes metadata.
    pub fn combine(left: &NodeData, right: &NodeData) -> NodeData {
        assert_eq!(left.consensus_branch_id, right.consensus_branch_id);
        let mut hash_buf = [0u8; MAX_NODE_DATA_SIZE * 2];
        let size = {
            let mut cursor = ::std::io::Cursor::new(&mut hash_buf[..]);
            left.write(&mut cursor)
                .expect("Writing to memory buf with enough length cannot fail; qed");
            right
                .write(&mut cursor)
                .expect("Writing to memory buf with enough length cannot fail; qed");
            cursor.position() as usize
        };
        let hash = blake2b_personal(
            &personalization(left.consensus_branch_id),
            &hash_buf[..size],
        );
        NodeData {
            consensus_branch_id: left.consensus_branch_id,
            subtree_commitment: hash,
            start_time: left.start_time,
            end_time: right.end_time,
            start_target: left.start_target,
            end_target: right.end_target,
            start_sapling_root: left.start_sapling_root,
            end_sapling_root: right.end_sapling_root,
            subtree_total_work: left.subtree_total_work + right.subtree_total_work,
            start_height: left.start_height,
            end_height: right.end_height,
            sapling_tx: left.sapling_tx + right.sapling_tx,
        }
    }
    fn write_compact<W: std::io::Write>(w: &mut W, compact: u64) -> std::io::Result<()> {
        match compact {
            0..=0xfc => w.write_all(&[compact as u8])?,
            0xfd..=0xffff => {
                w.write_all(&[0xfd])?;
                w.write_u16::<LittleEndian>(compact as u16)?;
            }
            0x10000..=0xffff_ffff => {
                w.write_all(&[0xfe])?;
                w.write_u32::<LittleEndian>(compact as u32)?;
            }
            _ => {
                w.write_all(&[0xff])?;
                w.write_u64::<LittleEndian>(compact)?;
            }
        }
        Ok(())
    }
    fn read_compact<R: std::io::Read>(reader: &mut R) -> std::io::Result<u64> {
        let result = match reader.read_u8()? {
            i @ 0..=0xfc => i.into(),
            0xfd => reader.read_u16::<LittleEndian>()?.into(),
            0xfe => reader.read_u32::<LittleEndian>()?.into(),
            _ => reader.read_u64::<LittleEndian>()?,
        };
        Ok(result)
    }
    /// Write to the byte representation.
    pub fn write<W: std::io::Write>(&self, w: &mut W) -> std::io::Result<()> {
        w.write_all(&self.subtree_commitment)?;
        w.write_u32::<LittleEndian>(self.start_time)?;
        w.write_u32::<LittleEndian>(self.end_time)?;
        w.write_u32::<LittleEndian>(self.start_target)?;
        w.write_u32::<LittleEndian>(self.end_target)?;
        w.write_all(&self.start_sapling_root)?;
        w.write_all(&self.end_sapling_root)?;
        let mut work_buf = [0u8; 32];
        self.subtree_total_work.to_little_endian(&mut work_buf[..]);
        w.write_all(&work_buf)?;
        Self::write_compact(w, self.start_height)?;
        Self::write_compact(w, self.end_height)?;
        Self::write_compact(w, self.sapling_tx)?;
        Ok(())
    }
    /// Read from the byte representation.
    pub fn read<R: std::io::Read>(consensus_branch_id: u32, r: &mut R) -> std::io::Result<Self> {
        let mut data = Self::default();
        data.consensus_branch_id = consensus_branch_id;
        r.read_exact(&mut data.subtree_commitment)?;
        data.start_time = r.read_u32::<LittleEndian>()?;
        data.end_time = r.read_u32::<LittleEndian>()?;
        data.start_target = r.read_u32::<LittleEndian>()?;
        data.end_target = r.read_u32::<LittleEndian>()?;
        r.read_exact(&mut data.start_sapling_root)?;
        r.read_exact(&mut data.end_sapling_root)?;
        let mut work_buf = [0u8; 32];
        r.read_exact(&mut work_buf)?;
        data.subtree_total_work = U256::from_little_endian(&work_buf);
        data.start_height = Self::read_compact(r)?;
        data.end_height = Self::read_compact(r)?;
        data.sapling_tx = Self::read_compact(r)?;
        Ok(data)
    }
    /// Convert to byte representation.
    pub fn to_bytes(&self) -> Vec<u8> {
        let mut buf = [0u8; MAX_NODE_DATA_SIZE];
        let pos = {
            let mut cursor = std::io::Cursor::new(&mut buf[..]);
            self.write(&mut cursor).expect("Cursor cannot fail");
            cursor.position() as usize
        };
        buf[0..pos].to_vec()
    }
    /// Convert from byte representation.
    pub fn from_bytes<T: AsRef<[u8]>>(consensus_branch_id: u32, buf: T) -> std::io::Result<Self> {
        let mut cursor = std::io::Cursor::new(buf);
        Self::read(consensus_branch_id, &mut cursor)
    }
    /// Hash node metadata
    pub fn hash(&self) -> [u8; 32] {
        let bytes = self.to_bytes();
        blake2b_personal(&personalization(self.consensus_branch_id), &bytes)
    }
 }
 #[cfg(test)]
 impl quickcheck::Arbitrary for NodeData {
    fn arbitrary<G: quickcheck::Gen>(gen: &mut G) -> Self {
        let mut node_data = NodeData::default();
        node_data.consensus_branch_id = 0;
        gen.fill_bytes(&mut node_data.subtree_commitment[..]);
        node_data.start_time = gen.next_u32();
        node_data.end_time = gen.next_u32();
        node_data.start_target = gen.next_u32();
        node_data.end_target = gen.next_u32();
        gen.fill_bytes(&mut node_data.start_sapling_root[..]);
        gen.fill_bytes(&mut node_data.end_sapling_root[..]);
        let mut number = [0u8; 32];
        gen.fill_bytes(&mut number[..]);
        node_data.subtree_total_work = U256::from_little_endian(&number[..]);
        node_data.start_height = gen.next_u64();
        node_data.end_height = gen.next_u64();
        node_data.sapling_tx = gen.next_u64();
        node_data
    }
 }
 #[cfg(test)]
 mod tests {
    use super::NodeData;
    use quickcheck::{quickcheck, TestResult};
    quickcheck! {
        fn serialization_round_trip(node_data: NodeData) -> TestResult {
            TestResult::from_bool(NodeData::from_bytes(0, &node_data.to_bytes()).unwrap() == node_data)
        }
    }
 }
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