def verify(self, signature, data, hash_context):
if not isinstance(hash_context, hashes.HashContext):
raise TypeError("hash_context must be an instance of hashes.HashContext.")
size = self.public_numbers.parameter_numbers.q.bit_length() // 8
r, s = (bytes_to_long(value) for value in read_content(signature, '{0}s{0}s'.format(size)))
# r, s = (bytes_to_long(value) for value in read_content(signature, '20s20s'))
hash_context.update(data)
digest = hash_context.finalize()
try:
self._key.verify(encode_dss_signature(r, s), digest, Prehashed(SHA256HMAC160()))
except InvalidSignature:
raise ValueError("invalid signature")
def verify(self, signature, data, hash_context):
if not isinstance(hash_context, hashes.HashContext):
raise TypeError("hash_context must be an instance of hashes.HashContext.")
size = self.public_numbers.parameter_numbers.q.bit_length() // 8
r, s = (bytes_to_long(value) for value in read_content(signature, '{0}s{0}s'.format(size)))
# r, s = (bytes_to_long(value) for value in read_content(signature, '20s20s'))
verifier = self._key.verifier(encode_dss_signature(r, s), hashes.SHA256())
verifier._hash_ctx = hash_context
verifier.update(data)
try:
verifier.verify()
except InvalidSignature:
raise ValueError("invalid signature")
def _decode_numbers(cls, encoded_numbers):
p, q, g, y = read_content(encoded_numbers, MPI, MPI, MPI, MPI)
public_numbers = dsa.DSAPublicNumbers(y, dsa.DSAParameterNumbers(p, q, g))
return public_numbers.public_key(cls.__backend__)
def _decode_numbers(cls, encoded_numbers):
p, q, g, y = read_content(encoded_numbers, MPI, MPI, MPI, MPI)
public_numbers = dsa.DSAPublicNumbers(y, dsa.DSAParameterNumbers(p, q, g))
return public_numbers.public_key(cls.__backend__)