def _CheckSig(sig,
pubkey,
script,
txTo,
inIdx,
flags,
err_raiser,
amount=0,
sigversion=SIGVERSION_BASE):
key = bitcointx.core.key.CPubKey(pubkey)
if len(sig) == 0:
return False
hashtype = sig[-1]
if flags & _STRICT_ENCODING_FLAGS:
verify_fn = key.verify
if not _IsValidSignatureEncoding(sig):
raise VerifyScriptError(
"signature DER encoding is not strictly valid")
if SCRIPT_VERIFY_STRICTENC in flags:
low_hashtype = hashtype & (~SIGHASH_ANYONECANPAY)
if low_hashtype < SIGHASH_ALL or low_hashtype > SIGHASH_SINGLE:
raise VerifyScriptError("unknown hashtype in signature")
if not _IsCompressedOrUncompressedPubKey(pubkey):
raise VerifyScriptError("unknown pubkey type")
else:
verify_fn = key.verify_nonstrict
if SCRIPT_VERIFY_WITNESS_PUBKEYTYPE in flags and sigversion == SIGVERSION_WITNESS_V0:
if not _IsCompressedPubKey(pubkey):
raise VerifyScriptError("witness pubkey is not compressed")
if SCRIPT_VERIFY_LOW_S in flags and not IsLowDERSignature(sig):
raise VerifyScriptError("signature is not low-S")
# Raw signature hash due to the SIGHASH_SINGLE bug
#
# Note that we never raise an exception if RawSignatureHash() returns an
# error code. However the first error code case, where inIdx >=
# len(txTo.vin), shouldn't ever happen during EvalScript() as that would
# imply the scriptSig being checked doesn't correspond to a valid txout -
# that should cause other validation machinery to fail long before we ever
# got here.
(h, err) = script.raw_sighash(txTo,
inIdx,
hashtype,
amount=amount,
sigversion=sigversion)
return verify_fn(h, sig[:-1])
def test_sign(self) -> None:
key = CBitcoinKey('5KJvsngHeMpm884wtkJNzQGaCErckhHJBGFsvd3VyK5qMZXj3hS')
hash = b'\x00' * 32
sig = key.sign(hash)
# Check a valid signature
self.assertTrue(key.pub.verify(hash, sig))
self.assertTrue(IsLowDERSignature(sig))
# Check that invalid hash returns false
self.assertFalse(key.pub.verify(b'\xFF'*32, sig))
# Check that invalid signature returns false.
#
# Note the one-in-four-billion chance of a false positive :)
self.assertFalse(key.pub.verify(hash, sig[0:-4] + b'\x00\x00\x00\x00'))
def test_low_s_value(self):
sig = x(
'3045022100b135074e08cc93904a1712b2600d3cb01899a5b1cc7498caa4b8585bcf5f27e7022074ab544045285baef0a63f0fb4c95e577dcbf5c969c0bf47c7da8e478909d669'
)
self.assertTrue(IsLowDERSignature(sig))
def test_high_s_value(self):
sig = x(
'3046022100820121109528efda8bb20ca28788639e5ba5b365e0a84f8bd85744321e7312c6022100a7c86a21446daa405306fe10d0a9906e37d1a2c6b6fdfaaf6700053058029bbe'
)
self.assertFalse(IsLowDERSignature(sig))