# This file is dual licensed under the terms of the Apache License, Version # 2.0, and the BSD License. See the LICENSE file in the root of this repository # for complete details. from __future__ import absolute_import, division, print_function import warnings from pyasn1.codec.der import decoder, encoder from pyasn1.error import PyAsn1Error from pyasn1.type import namedtype, univ import six from cryptography import utils from cryptography.hazmat.primitives import hashes class _DSSSigValue(univ.Sequence): componentType = namedtype.NamedTypes( namedtype.NamedType('r', univ.Integer()), namedtype.NamedType('s', univ.Integer()) ) def decode_rfc6979_signature(signature): warnings.warn( "decode_rfc6979_signature is deprecated and will " "be removed in a future version, use decode_dss_signature instead.", utils.DeprecatedIn10, stacklevel=2 ) return decode_dss_signature(signature) def decode_dss_signature(signature): try: data, remaining = decoder.decode(signature, asn1Spec=_DSSSigValue()) except PyAsn1Error: raise ValueError("Invalid signature data. Unable to decode ASN.1") if remaining: raise ValueError( "The signature contains bytes after the end of the ASN.1 sequence." ) r = int(data.getComponentByName('r')) s = int(data.getComponentByName('s')) return (r, s) def encode_rfc6979_signature(r, s): warnings.warn( "encode_rfc6979_signature is deprecated and will " "be removed in a future version, use encode_dss_signature instead.", utils.DeprecatedIn10, stacklevel=2 ) return encode_dss_signature(r, s) def encode_dss_signature(r, s): if ( not isinstance(r, six.integer_types) or not isinstance(s, six.integer_types) ): raise ValueError("Both r and s must be integers") sig = _DSSSigValue() sig.setComponentByName('r', r) sig.setComponentByName('s', s) return encoder.encode(sig) class Prehashed(object): def __init__(self, algorithm): if not isinstance(algorithm, hashes.HashAlgorithm): raise TypeError("Expected instance of HashAlgorithm.") self._algorithm = algorithm self._digest_size = algorithm.digest_size digest_size = utils.read_only_property("_digest_size")