// Verifies a hash using DER encoded signature
func verifyECDSA(pubKey, signature, hash []byte) (bool, error) {
sig, err := btcec.ParseDERSignature(signature, btcec.S256())
if err != nil {
return false, err
}
pk, err := btcec.ParsePubKey(pubKey, btcec.S256())
if err != nil {
return false, nil
}
return sig.Verify(hash, pk), nil
}
func (pubKey PubKeySecp256k1) VerifyBytes(msg []byte, sig_ Signature) bool {
pub__, err := secp256k1.ParsePubKey(append([]byte{0x04}, pubKey[:]...), secp256k1.S256())
if err != nil {
return false
}
sig, ok := sig_.(SignatureSecp256k1)
if !ok {
return false
}
sig__, err := secp256k1.ParseDERSignature(sig[:], secp256k1.S256())
if err != nil {
return false
}
return sig__.Verify(Sha256(msg), pub__)
}
func TestSignatures(t *testing.T) {
for _, test := range signatureTests {
var err error
if test.der {
_, err = btcec.ParseDERSignature(test.sig, btcec.S256())
} else {
_, err = btcec.ParseSignature(test.sig, btcec.S256())
}
if err != nil {
if test.isValid {
t.Errorf("%s signature failed when shouldn't %v",
test.name, err)
} /* else {
t.Errorf("%s got error %v", test.name, err)
} */
continue
}
if !test.isValid {
t.Errorf("%s counted as valid when it should fail",
test.name)
}
}
}
// mergeMultiSig combines the two signature scripts sigScript and prevScript
// that both provide signatures for pkScript in output idx of tx. addresses
// and nRequired should be the results from extracting the addresses from
// pkScript. Since this function is internal only we assume that the arguments
// have come from other functions internally and thus are all consistent with
// each other, behaviour is undefined if this contract is broken.
func mergeMultiSig(tx *wire.MsgTx, idx int, addresses []btcutil.Address,
nRequired int, pkScript, sigScript, prevScript []byte) []byte {
// This is an internal only function and we already parsed this script
// as ok for multisig (this is how we got here), so if this fails then
// all assumptions are broken and who knows which way is up?
pkPops, _ := parseScript(pkScript)
sigPops, err := parseScript(sigScript)
if err != nil || len(sigPops) == 0 {
return prevScript
}
prevPops, err := parseScript(prevScript)
if err != nil || len(prevPops) == 0 {
return sigScript
}
// Convenience function to avoid duplication.
extractSigs := func(pops []parsedOpcode, sigs [][]byte) [][]byte {
for _, pop := range pops {
if len(pop.data) != 0 {
sigs = append(sigs, pop.data)
}
}
return sigs
}
possibleSigs := make([][]byte, 0, len(sigPops)+len(prevPops))
possibleSigs = extractSigs(sigPops, possibleSigs)
possibleSigs = extractSigs(prevPops, possibleSigs)
// Now we need to match the signatures to pubkeys, the only real way to
// do that is to try to verify them all and match it to the pubkey
// that verifies it. we then can go through the addresses in order
// to build our script. Anything that doesn't parse or doesn't verify we
// throw away.
addrToSig := make(map[string][]byte)
sigLoop:
for _, sig := range possibleSigs {
// can't have a valid signature that doesn't at least have a
// hashtype, in practise it is even longer than this. but
// that'll be checked next.
if len(sig) < 1 {
continue
}
tSig := sig[:len(sig)-1]
hashType := SigHashType(sig[len(sig)-1])
pSig, err := btcec.ParseDERSignature(tSig, btcec.S256())
if err != nil {
continue
}
// We have to do this each round since hash types may vary
// between signatures and so the hash will vary. We can,
// however, assume no sigs etc are in the script since that
// would make the transaction nonstandard and thus not
// MultiSigTy, so we just need to hash the full thing.
hash := calcSignatureHash(pkPops, hashType, tx, idx)
for _, addr := range addresses {
// All multisig addresses should be pubkey addresses
// it is an error to call this internal function with
// bad input.
pkaddr := addr.(*btcutil.AddressPubKey)
pubKey := pkaddr.PubKey()
// If it matches we put it in the map. We only
// can take one signature per public key so if we
// already have one, we can throw this away.
if pSig.Verify(hash, pubKey) {
aStr := addr.EncodeAddress()
if _, ok := addrToSig[aStr]; !ok {
addrToSig[aStr] = sig
}
continue sigLoop
}
}
}
// Extra opcode to handle the extra arg consumed (due to previous bugs
// in the reference implementation).
builder := NewScriptBuilder().AddOp(OP_FALSE)
doneSigs := 0
// This assumes that addresses are in the same order as in the script.
for _, addr := range addresses {
sig, ok := addrToSig[addr.EncodeAddress()]
if !ok {
continue
}
builder.AddData(sig)
doneSigs++
if doneSigs == nRequired {
break
}
}
// padding for missing ones.
for i := doneSigs; i < nRequired; i++ {
builder.AddOp(OP_0)
}
script, _ := builder.Script()
return script
}