BinaryData CryptoECDSA::ECAddPoints(BinaryData const & Ax,
BinaryData const & Ay,
BinaryData const & Bx,
BinaryData const & By)
{
CryptoPP::ECP ecp = Get_secp256k1_ECP();
CryptoPP::Integer intAx, intAy, intBx, intBy, intCx, intCy;
intAx.Decode(Ax.getPtr(), Ax.getSize(), UNSIGNED);
intAy.Decode(Ay.getPtr(), Ay.getSize(), UNSIGNED);
intBx.Decode(Bx.getPtr(), Bx.getSize(), UNSIGNED);
intBy.Decode(By.getPtr(), By.getSize(), UNSIGNED);
BTC_ECPOINT A(intAx, intAy);
BTC_ECPOINT B(intBx, intBy);
BTC_ECPOINT C = ecp.Add(A,B);
BinaryData Cbd(64);
C.x.Encode(Cbd.getPtr(), 32, UNSIGNED);
C.y.Encode(Cbd.getPtr()+32, 32, UNSIGNED);
return Cbd;
}
SecureBinaryData CryptoECDSA::CompressPoint(SecureBinaryData const & pubKey65)
{
CryptoPP::ECP ecp = Get_secp256k1_ECP();
BTC_ECPOINT ptPub;
ecp.DecodePoint(ptPub, (byte*)pubKey65.getPtr(), 65);
SecureBinaryData ptCompressed(33);
ecp.EncodePoint((byte*)ptCompressed.getPtr(), ptPub, true);
return ptCompressed;
}
void StackInterpreter::op_checksig()
{
//pop sig and pubkey from the stack
if (stack_.size() < 2)
throw ScriptException("insufficient stack size for checksig operation");
auto&& pubkey = pop_back();
auto&& sigScript = pop_back();
if (sigScript.getSize() < 65)
{
stack_.push_back(move(intToRawBinary(false)));
return;
}
txInEvalState_.n_ = 1;
txInEvalState_.m_ = 1;
//extract sig and sighash type
BinaryRefReader brrSig(sigScript);
auto sigsize = sigScript.getSize() - 1;
auto sig = brrSig.get_BinaryDataRef(sigsize);
auto hashType = getSigHashSingleByte(brrSig.get_uint8_t());
//get data for sighash
if (sigHashDataObject_ == nullptr)
sigHashDataObject_ = make_shared<SigHashDataLegacy>();
auto&& sighashdata =
sigHashDataObject_->getDataForSigHash(hashType, *txStubPtr_,
outputScriptRef_, inputIndex_);
//prepare pubkey
BTC_ECPOINT ptPub;
CryptoPP::ECP ecp = CryptoECDSA::Get_secp256k1_ECP();
ecp.DecodePoint(ptPub, (byte*)pubkey.getPtr(), pubkey.getSize());
BTC_PUBKEY cppPubKey;
cppPubKey.Initialize(CryptoPP::ASN1::secp256k1(), ptPub);
//check point validity
/*BTC_PRNG prng;
if (!cppPubKey.Validate(prng, 3))
throw ScriptException("invalid pubkey");*/
//check signature
auto&& rs = BtcUtils::extractRSFromDERSig(sig);
bool result = CryptoECDSA().VerifyData(sighashdata, rs, cppPubKey);
stack_.push_back(move(intToRawBinary(result)));
if (result)
txInEvalState_.pubKeyState_.insert(make_pair(pubkey, true));
}
BinaryData CryptoECDSA::ECInverse(BinaryData const & Ax,
BinaryData const & Ay)
{
CryptoPP::ECP ecp = Get_secp256k1_ECP();
CryptoPP::Integer intAx, intAy, intCx, intCy;
intAx.Decode(Ax.getPtr(), Ax.getSize(), UNSIGNED);
intAy.Decode(Ay.getPtr(), Ay.getSize(), UNSIGNED);
BTC_ECPOINT A(intAx, intAy);
BTC_ECPOINT C = ecp.Inverse(A);
BinaryData Cbd(64);
C.x.Encode(Cbd.getPtr(), 32, UNSIGNED);
C.y.Encode(Cbd.getPtr()+32, 32, UNSIGNED);
return Cbd;
}
BinaryData CryptoECDSA::ECMultiplyPoint(BinaryData const & A,
BinaryData const & Bx,
BinaryData const & By)
{
CryptoPP::ECP ecp = Get_secp256k1_ECP();
CryptoPP::Integer intA, intBx, intBy, intCx, intCy;
intA.Decode( A.getPtr(), A.getSize(), UNSIGNED);
intBx.Decode(Bx.getPtr(), Bx.getSize(), UNSIGNED);
intBy.Decode(By.getPtr(), By.getSize(), UNSIGNED);
BTC_ECPOINT B(intBx, intBy);
BTC_ECPOINT C = ecp.ScalarMultiply(B, intA);
BinaryData Cbd(64);
C.x.Encode(Cbd.getPtr(), 32, UNSIGNED);
C.y.Encode(Cbd.getPtr()+32, 32, UNSIGNED);
return Cbd;
}
void StackInterpreter::op_checkmultisig()
{
//stack needs to have at least m, n, output script
if (stack_.size() < 3)
throw ScriptException("insufficient stack size for checkmultisig operation");
//pop n
auto&& n = pop_back();
auto nI = rawBinaryToInt(n);
if (nI < 0 || nI > 20)
throw ScriptException("invalid n");
//pop pubkeys
map<unsigned, pair<BTC_PUBKEY, BinaryData>> pubkeys;
for (unsigned i = 0; i < nI; i++)
{
auto&& pubkey = pop_back();
CryptoPP::ECP ecp = CryptoECDSA::Get_secp256k1_ECP();
BTC_ECPOINT ptPub;
ecp.DecodePoint(ptPub, (byte*)pubkey.getPtr(), pubkey.getSize());
BTC_PUBKEY cppPubKey;
cppPubKey.Initialize(CryptoPP::ASN1::secp256k1(), ptPub);
BTC_PRNG prng;
if (cppPubKey.Validate(prng, 3))
{
txInEvalState_.pubKeyState_.insert(make_pair(pubkey, false));
auto&& pubkeypair = make_pair(move(cppPubKey), pubkey);
pubkeys.insert(move(make_pair(i, move(pubkeypair))));
}
}
//pop m
auto&& m = pop_back();
auto mI = rawBinaryToInt(m);
if (mI < 0 || mI > nI)
throw ScriptException("invalid m");
txInEvalState_.n_ = nI;
txInEvalState_.m_ = mI;
//pop sigs
struct sigData
{
BinaryData sig_;
SIGHASH_TYPE hashType_;
};
vector<sigData> sigVec;
while (stack_.size() > 0)
{
auto&& sig = pop_back();
if (sig.getSize() == 0)
break;
sigData sdata;
sdata.sig_ = sig.getSliceCopy(0, sig.getSize() - 1);
//grab hash type
sdata.hashType_ =
getSigHashSingleByte(*(sig.getPtr() + sig.getSize() - 1));
//push to vector
sigVec.push_back(move(sdata));
}
//should have at least as many sigs as m
/*if (sigVec.size() < mI)
throw ScriptException("invalid sig count");*/
//check sigs
map<SIGHASH_TYPE, BinaryData> dataToHash;
//check sighashdata object
if (sigHashDataObject_ == nullptr)
sigHashDataObject_ = make_shared<SigHashDataLegacy>();
unsigned validSigCount = 0;
int index = nI - 1;
auto sigIter = sigVec.rbegin();
while(sigIter != sigVec.rend())
{
auto& sigD = *sigIter++;
//get data to hash
auto& hashdata = dataToHash[sigD.hashType_];
if (hashdata.getSize() == 0)
{
hashdata = sigHashDataObject_->getDataForSigHash(
sigD.hashType_, *txStubPtr_, outputScriptRef_, inputIndex_);
}
//prepare sig
auto&& rs = BtcUtils::extractRSFromDERSig(sigD.sig_);
BinaryWriter sigW;
//pop pubkeys from deque to verify against sig
while (pubkeys.size() > 0)
{
auto pubkey = pubkeys[index];
pubkeys.erase(index--);
#ifdef SIGNER_DEBUG
LOGWARN << "Verifying sig for: ";
LOGWARN << " pubkey: " << pubkey.second.toHexStr();
auto&& msg_hash = BtcUtils::getHash256(hashdata);
LOGWARN << " message: " << hashdata.toHexStr();
#endif
if (CryptoECDSA().VerifyData(hashdata, rs, pubkey.first))
{
txInEvalState_.pubKeyState_[pubkey.second] = true;
validSigCount++;
break;
}
}
}
if (validSigCount >= mI)
op_true();
else
op_0();
}
