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Precompute sighashes

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Original version by Nicolas Dorier. Precomputing version by Pieter Wuille.

Edited for Zcash by Ariel Gabizon and Jack Grigg
This commit is contained in:
Pieter Wuille
2018-01-01 13:27:59 +02:00
committed by Jack Grigg
parent 722d811f89
commit f762d44973
10 changed files with 84 additions and 38 deletions
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54
src/script/interpreter.cpp
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@@ -1050,9 +1050,40 @@ public:
}
};
uint256 GetPrevoutHash(const CTransaction& txTo) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].prevout;
}
return ss.GetHash();
}
uint256 GetSequenceHash(const CTransaction& txTo) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].nSequence;
}
return ss.GetHash();
}
uint256 GetOutputsHash(const CTransaction& txTo) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vout.size(); n++) {
ss << txTo.vout[n];
}
return ss.GetHash();
}
} // anon namespace
uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion)
CachedHashes::CachedHashes(const CTransaction& txTo)
{
hashPrevouts = GetPrevoutHash(txTo);
hashSequence = GetSequenceHash(txTo);
hashOutputs = GetOutputsHash(txTo);
}
uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion, const CachedHashes* cache)
{
if (nIn >= txTo.vin.size() && nIn != NOT_AN_INPUT) {
// nIn out of range
@@ -1065,27 +1096,16 @@ uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsig
uint256 hashOutputs;
if (!(nHashType & SIGHASH_ANYONECANPAY)) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].prevout;
}
hashPrevouts = ss.GetHash(); // TODO: cache this value for all signatures in a transaction
hashPrevouts = cache ? cache->hashPrevouts : GetPrevoutHash(txTo);
}
if (!(nHashType & SIGHASH_ANYONECANPAY) && (nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].nSequence;
}
hashSequence = ss.GetHash(); // TODO: cache this value for all signatures in a transaction
hashSequence = cache ? cache->hashSequence : GetSequenceHash(txTo);
}
if ((nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vout.size(); n++) {
ss << txTo.vout[n];
}
hashOutputs = ss.GetHash(); // TODO: cache this value for all signatures in a transaction
hashOutputs = cache ? cache->hashOutputs : GetOutputsHash(txTo);
} else if ((nHashType & 0x1f) == SIGHASH_SINGLE && nIn < txTo.vout.size()) {
CHashWriter ss(SER_GETHASH, 0);
ss << txTo.vout[nIn];
@@ -1154,7 +1174,7 @@ bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn
uint256 sighash;
try {
sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion);
sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion, this->cachedHashes);
} catch (logic_error ex) {
return false;
}