def verify(self, signature, digest) -> bool:
""" Verify that a signature is valid for a 32 byte digest. """
if len(signature) != 64:
raise ValueError('Signature must be 64 bytes long.')
if len(digest) != 32:
raise ValueError('Digest must be 32 bytes long.')
key = self.verifying_key
raw_signature = libsecp256k1_ffi.new('secp256k1_ecdsa_signature *')
parsed = libsecp256k1.secp256k1_ecdsa_signature_parse_compact(
key.context.ctx, raw_signature, signature)
assert parsed == 1
normalized_signature = libsecp256k1_ffi.new(
'secp256k1_ecdsa_signature *')
libsecp256k1.secp256k1_ecdsa_signature_normalize(
key.context.ctx, normalized_signature, raw_signature)
verified = libsecp256k1.secp256k1_ecdsa_verify(key.context.ctx,
normalized_signature,
digest, key.public_key)
return bool(verified)
def sign_compact(self, digest):
""" Produce a compact signature. """
key = self.signing_key
signature = libsecp256k1_ffi.new('secp256k1_ecdsa_signature *')
signed = libsecp256k1.secp256k1_ecdsa_sign(key.context.ctx, signature,
digest, key.secret,
libsecp256k1_ffi.NULL,
libsecp256k1_ffi.NULL)
if not signed:
raise ValueError('The private key was invalid.')
serialized = libsecp256k1_ffi.new('unsigned char[%d]' %
CDATA_SIG_LENGTH)
compacted = libsecp256k1.secp256k1_ecdsa_signature_serialize_compact(
key.context.ctx, serialized, signature)
if compacted != 1:
raise ValueError('The signature could not be compacted.')
return bytes(libsecp256k1_ffi.buffer(serialized, CDATA_SIG_LENGTH))