bool CheckSig(vector<unsigned char> vchSig, const vector<unsigned char> &vchPubKey, const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, int flags)
{
static CSignatureCache signatureCache;
CPubKey pubkey(vchPubKey);
if (!pubkey.IsValid())
return false;
// Hash type is one byte tacked on to the end of the signature
if (vchSig.empty())
return false;
if (nHashType == 0)
nHashType = vchSig.back();
else if (nHashType != vchSig.back())
return false;
vchSig.pop_back();
uint256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType);
if (signatureCache.Get(sighash, vchSig, pubkey))
return true;
if (!pubkey.Verify(sighash, vchSig))
return false;
if (!(flags & SCRIPT_VERIFY_NOCACHE))
signatureCache.Set(sighash, vchSig, pubkey);
return true;
}
bool CachingTransactionSignatureChecker::VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const
{
static CSignatureCache signatureCache;
if (signatureCache.Get(sighash, vchSig, pubkey))
return true;
if (!TransactionSignatureChecker::VerifySignature(vchSig, pubkey, sighash))
return false;
if (store)
signatureCache.Set(sighash, vchSig, pubkey);
return true;
}
bool CachingTransactionSignatureChecker::VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const
{
static CSignatureCache signatureCache;
uint256 entry;
signatureCache.ComputeEntry(entry, sighash, vchSig, pubkey);
if (signatureCache.Get(entry)) {
if (!store) {
signatureCache.Erase(entry);
}
return true;
}
if (!TransactionSignatureChecker::VerifySignature(vchSig, pubkey, sighash))
return false;
if (store) {
signatureCache.Set(entry);
}
return true;
}