Tweaks to difficulty adjustment algorithm
This PR changes the difficulty algorithm to adjust from the average difficulty over the
block window instead of from the last difficulty. It also removes the special rules for the
testnet, which are incompatible with difficulty averaging.
Closes#147 again.
The min-difficulty blocks are incompatible with difficulty averaging.
Network difficulty is also now defined as the difficulty the network is
currently working to solve, rather than the last non-min-difficulty block
difficulty.
Separate concepts of block difficulty and network difficulty in RPC
"Block difficulty" is the difficulty listed in a block's header, which in the
testnet can sometimes be min-difficulty (if time-since-last-block is too large).
"Network difficulty" is the difficulty that the network was trying to satisfy
at a particular block height. In mainnet this is always equal to the difficulty
of the solved block for that height, but in testnet the network difficulty is
derived from the last non-min-difficulty block difficulty.
This commit fixes the RPC APIs that are intended to show network difficulty, so
that on testnet they don't sometimes drop to 1.0, confusing users.
Closes#1181
Output Equihash solution in RPC results as a hex string
When the Equihash solution was changed to a compact form in #1175, the block header changed from storing a vector of indices to a vector of chars. `blockToJSON()` was not updated, which meant that RPC calls like `getblock` returned the solution as a list of 1344 integers.
This PR changes `blockToJSON()` to output the Equihash solution as a hex string, identical to how it appears in the block header.
The genesis blocks and miner tests have been regenerated, because changing the
block header serialisation format changes the block hash, and thus validity.
The Equihash solutions have been removed from the bloom test inputs for
simplicity (block validity is not checked there; only a valid serialisation is
necessary).
Changes:
- floor(512/n)*n/8 bytes of BLAKE2b output is split between floor(512/n)
adjacent indices, instead of using one hash call per index.
- Parameters with n/(k+1) mod 8 != 0 will expand the BLAKE2b output to byte
boundaries for colliding, instead of using a longer output and clearing bits.
- The genesis blocks have been regenerated.
- The test vectors have been regenerated.
- The Equihash inputs for the cancellation tests were modified to ensure that
valid solutions were available to exercise the full solver.
Add gtest for non-malleable txids.
1. Test txid of normal transaction is double sha256 with sigscript input data removed
2. Test txid of coinbase transaction is double sha256 over whole tx
You can run a single test with:
./zcash-gtest --gtest_filter="txid_tests*"
