This was unintentionally committed, and caused Equihash verification of blocks
without parents to be skipped. This only affects the genesis block on the test
network, but also causes the "time verifyequihash" benchmark to incorrectly
appear instantaneous.
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.
This version works, but generates the initial rows in a way that is not what we
want to specify. See #1175 for resolving this.
Co-author: Daira Hopwood <daira@jacaranda.org>
When the difficulty adjustment algorithm was altered, the special testnet
min-difficulty case was maintained, but the difficulty adjustment for the
following block then adjusted from min-difficulty instead of from the last
non-min-difficulty block. This caused the difficulty on the testnet to sawtooth
instead of stabilising. The intended behaviour is restored here.
The top and bottom 16 bits of the nonce are left clear for local use as thread
flags and counters. This does not leak any more local information about the
miner than is currently exposed.
The cleared bits should not be considered a consensus rule, as miners are free
to set all bits of the nonce however they wish.
Closes#1033
Includes a tweak to set the fixed-width of the rows based on whether the first
or last round is widest. This is necessary for some parameters, these ones
included.
This field has no defined semantics. While it was added as a result of
discussions about merged mining in #724, this field will not necessarily ever be
used for that purpose.
This reduces the peak number of lists in-memory from 2^k to k, and enables the
solver to eliminate most duplicates before it has instantiated the full set of
leaves.
After a new block is found or after a few nonces have been tried (currently
after every nonce), the miner checks for global changes. If any of these are
triggered, a new block is built from scratch, which re-initialises the Equihash
input. But if none of the checks are triggered, the miner just updates nTime and
continues mining - without updating the Equihash input to account for the new
block header. This bugfix corrects the behaviour by regenerating the Equihash
input in both situations.
Changing the order of difficulty calculation operations to divide first doesn't
affect the result significantly, but ensures we never overflow the arith_uint256
during multiplication and get an artificial jump in difficulty.
Changes to bloom tests were done by running the following commands:
sed -i 's/\(CDataStream stream(ParseHex(".\{152\}\)\(.\{8\}\)/\100000000000000000000000000000000000000000000000000000000\200/' src/test/bloom_tests.cpp
sed -i 's/\(vector<unsigned char> vch = ParseHex(".\{152\}\)\(.\{8\}\)/\100000000000000000000000000000000000000000000000000000000\200/' src/test/bloom_tests.cpp
and then reverting the single change to the transaction line.
Jack Grigg