Merge pull request #3637

6fd7ef2 Also switch the (unused) verification code to low-s instead of even-s. (Pieter Wuille)
This commit is contained in:
Wladimir J. van der Laan
2014-05-09 16:24:46 +02:00
5 changed files with 78 additions and 25 deletions

View File

@@ -286,9 +286,12 @@ bool IsCanonicalSignature(const valtype &vchSig, unsigned int flags) {
if (nLenS > 1 && (S[0] == 0x00) && !(S[1] & 0x80))
return error("Non-canonical signature: S value excessively padded");
if (flags & SCRIPT_VERIFY_EVEN_S) {
if (S[nLenS-1] & 1)
return error("Non-canonical signature: S value odd");
if (flags & SCRIPT_VERIFY_LOW_S) {
// If the S value is above the order of the curve divided by two, its
// complement modulo the order could have been used instead, which is
// one byte shorter when encoded correctly.
if (!CKey::CheckSignatureElement(S, nLenS, true))
return error("Non-canonical signature: S value is unnecessarily high");
}
return true;