Do signature-s negation inside the tests

To avoid the need for libsecp256k1 to expose such functionality.
This commit is contained in:
Pieter Wuille
2014-11-05 10:53:59 -08:00
parent 5406f61373
commit f4e0aefadc
5 changed files with 52 additions and 7 deletions

View File

@@ -95,6 +95,48 @@ void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, int flags, bo
BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, flags, SignatureChecker(BuildSpendingTransaction(scriptSig, BuildCreditingTransaction(scriptPubKey)), 0)) == expect, message);
}
void static NegateSignatureS(std::vector<unsigned char>& vchSig) {
// Parse the signature.
std::vector<unsigned char> r, s;
r = std::vector<unsigned char>(vchSig.begin() + 4, vchSig.begin() + 4 + vchSig[3]);
s = std::vector<unsigned char>(vchSig.begin() + 6 + vchSig[3], vchSig.begin() + 6 + vchSig[3] + vchSig[5 + vchSig[3]]);
unsigned char hashtype = vchSig.back();
// Really ugly to implement mod-n negation here, but it would be feature creep to expose such functionality from libsecp256k1.
static const unsigned char order[33] = {
0x00,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE,
0xBA, 0xAE, 0xDC, 0xE6, 0xAF, 0x48, 0xA0, 0x3B,
0xBF, 0xD2, 0x5E, 0x8C, 0xD0, 0x36, 0x41, 0x41
};
while (s.size() < 33) {
s.insert(s.begin(), 0x00);
}
int carry = 0;
for (int p = 32; p >= 1; p--) {
int n = (int)order[p] - s[p] - carry;
s[p] = (n + 256) & 0xFF;
carry = (n < 0);
}
assert(carry == 0);
if (s.size() > 1 && s[0] == 0 && s[1] < 0x80) {
s.erase(s.begin());
}
// Reconstruct the signature.
vchSig.clear();
vchSig.push_back(0x30);
vchSig.push_back(4 + r.size() + s.size());
vchSig.push_back(0x02);
vchSig.push_back(r.size());
vchSig.insert(vchSig.end(), r.begin(), r.end());
vchSig.push_back(0x02);
vchSig.push_back(s.size());
vchSig.insert(vchSig.end(), s.begin(), s.end());
vchSig.push_back(hashtype);
}
namespace
{
const unsigned char vchKey0[32] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
@@ -194,7 +236,10 @@ public:
uint256 hash = SignatureHash(scriptPubKey, spendTx, 0, nHashType);
std::vector<unsigned char> vchSig, r, s;
do {
key.Sign(hash, vchSig, lenS <= 32);
key.Sign(hash, vchSig);
if ((lenS == 33) != (vchSig[5 + vchSig[3]] == 33)) {
NegateSignatureS(vchSig);
}
r = std::vector<unsigned char>(vchSig.begin() + 4, vchSig.begin() + 4 + vchSig[3]);
s = std::vector<unsigned char>(vchSig.begin() + 6 + vchSig[3], vchSig.begin() + 6 + vchSig[3] + vchSig[5 + vchSig[3]]);
} while (lenR != r.size() || lenS != s.size());