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ff/README.md

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+# ff
+
+`ff` is a finite field library written in pure Rust, with no `unsafe{}` code.
+
+## Disclaimers
+
+* This library does not provide constant-time guarantees.
+
+## Usage
+
+Add the `ff` crate to your `Cargo.toml`:
+
+```toml
+[dependencies]
+ff = "0.4"
+```
+
+The `ff` crate contains `Field`, `PrimeField`, `PrimeFieldRepr` and `SqrtField` traits. See the **[documentation](https://docs.rs/ff/0.4.0/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.
+
+First, enable the `derive` crate feature:
+
+```toml
+[dependencies]
+ff = { version = "0.4", features = ["derive"] }
+```
+
+And then use the macro like so:
+
+```rust
+extern crate rand;
+#[macro_use]
+extern crate ff;
+
+#[derive(PrimeField)]
+#[PrimeFieldModulus = "52435875175126190479447740508185965837690552500527637822603658699938581184513"]
+#[PrimeFieldGenerator = "7"]
+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.
+
+## 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.