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.
Deallocate the public parameters during Shutdown.
This also has it deallocated in `GenerateParams` and `test_bitcoin`. The virtual destructor probably isn't necessary but I added it just in case we need it some other time.
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.
A fix for transaction malleability
This PR fixes transaction malleability by not including the sigscript of transaction inputs and joinsplit sigs when hashing the txid.
This PR supercedes PR #1101 which was a minimal solution based on a new serialization flag.
This PR introduces GetTxid() to distinguish between getting a transaction id and the double sha256 hash.
The key changes are:
- Adding GetTxid() method to CTransaction which makes a copy of the transaction, clearing out the sigscript and joinsplitsig fields, before hashing.
- Verifying that every call to GetHash() actually wants a txid, and replacing with GetTxid().
- Renaming GetHash() to GetSerializeHash()
- Rationale: In future, upstream code we want to merge will use GetHash() but we don't know the intent. We should check to see if the intent is to receive a txid (most likely) in which case we replace with GetTxid(), or if upstream actually wants a double hash of the transaction we can use GetSerializeHash().
- Updated genesis data in chainparams.cpp
Note that coinbase transactions are excluded as they need the sigscript hashed to help avoid duplicate txids per BIP34:
- This modification is related to a question from @ebfull on PR #1101 - "Can we think of a way this change allows us to construct two transactions with the same txid which can simultaneously appear in the blockchain? My guess is it would be possible to construct a coinbase transaction of such a form... this surely breaks invariants."
This PR Passes all tests in test_bitcoin (test data was updated in bloom_tests, miner_tests and script_tests).
Collect all permutations of final solutions
This fixes a small bug where if there was a three-way (or more) collision in the final step, one or more valid solutions would be left out.
New private/public key pairs for broadcasting alert messages
Implements #424
Fixes and integrates method of sending alerts as described by upstream here:
- https://gist.github.com/laanwj/0e689cfa37b52bcbbb44
To send an alert:
- Copy private keys into alertkeys.h.
- Modify alert parameters and message found in sendalert.cpp
- Build and run to send the alert e.g. ./zcashd -printtoconsole -sendalert
Tested and verified with local nodes on alpha 6 testnet.
