File Content: dsa.py # 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 abc import six from cryptography import utils @six.add_metaclass(abc.ABCMeta) class DSAParameters(object): @abc.abstractmethod def generate_private_key(self): """ Generates and returns a DSAPrivateKey. """ @six.add_metaclass(abc.ABCMeta) class DSAParametersWithNumbers(DSAParameters): @abc.abstractmethod def parameter_numbers(self): """ Returns a DSAParameterNumbers. """ @six.add_metaclass(abc.ABCMeta) class DSAPrivateKey(object): @abc.abstractproperty def key_size(self): """ The bit length of the prime modulus. """ @abc.abstractmethod def public_key(self): """ The DSAPublicKey associated with this private key. """ @abc.abstractmethod def parameters(self): """ The DSAParameters object associated with this private key. """ @abc.abstractmethod def signer(self, signature_algorithm): """ Returns an AsymmetricSignatureContext used for signing data. """ @abc.abstractmethod def sign(self, data, algorithm): """ Signs the data """ @six.add_metaclass(abc.ABCMeta) class DSAPrivateKeyWithSerialization(DSAPrivateKey): @abc.abstractmethod def private_numbers(self): """ Returns a DSAPrivateNumbers. """ @abc.abstractmethod def private_bytes(self, encoding, format, encryption_algorithm): """ Returns the key serialized as bytes. """ @six.add_metaclass(abc.ABCMeta) class DSAPublicKey(object): @abc.abstractproperty def key_size(self): """ The bit length of the prime modulus. """ @abc.abstractmethod def parameters(self): """ The DSAParameters object associated with this public key. """ @abc.abstractmethod def verifier(self, signature, signature_algorithm): """ Returns an AsymmetricVerificationContext used for signing data. """ @abc.abstractmethod def public_numbers(self): """ Returns a DSAPublicNumbers. """ @abc.abstractmethod def public_bytes(self, encoding, format): """ Returns the key serialized as bytes. """ @abc.abstractmethod def verify(self, signature, data, algorithm): """ Verifies the signature of the data. """ DSAPublicKeyWithSerialization = DSAPublicKey def generate_parameters(key_size, backend): return backend.generate_dsa_parameters(key_size) def generate_private_key(key_size, backend): return backend.generate_dsa_private_key_and_parameters(key_size) def _check_dsa_parameters(parameters): if parameters.p.bit_length() not in [1024, 2048, 3072]: raise ValueError("p must be exactly 1024, 2048, or 3072 bits long") if parameters.q.bit_length() not in [160, 224, 256]: raise ValueError("q must be exactly 160, 224, or 256 bits long") if not (1 < parameters.g < parameters.p): raise ValueError("g, p don't satisfy 1 < g < p.") def _check_dsa_private_numbers(numbers): parameters = numbers.public_numbers.parameter_numbers _check_dsa_parameters(parameters) if numbers.x <= 0 or numbers.x >= parameters.q: raise ValueError("x must be > 0 and < q.") if numbers.public_numbers.y != pow(parameters.g, numbers.x, parameters.p): raise ValueError("y must be equal to (g ** x % p).") class DSAParameterNumbers(object): def __init__(self, p, q, g): if ( not isinstance(p, six.integer_types) or not isinstance(q, six.integer_types) or not isinstance(g, six.integer_types) ): raise TypeError( "DSAParameterNumbers p, q, and g arguments must be integers." ) self._p = p self._q = q self._g = g p = utils.read_only_property("_p") q = utils.read_only_property("_q") g = utils.read_only_property("_g") def parameters(self, backend): return backend.load_dsa_parameter_numbers(self) def __eq__(self, other): if not isinstance(other, DSAParameterNumbers): return NotImplemented return self.p == other.p and self.q == other.q and self.g == other.g def __ne__(self, other): return not self == other def __repr__(self): return ( "<DSAParameterNumbers(p={self.p}, q={self.q}, g={self.g})>".format( self=self ) ) class DSAPublicNumbers(object): def __init__(self, y, parameter_numbers): if not isinstance(y, six.integer_types): raise TypeError("DSAPublicNumbers y argument must be an integer.") if not isinstance(parameter_numbers, DSAParameterNumbers): raise TypeError( "parameter_numbers must be a DSAParameterNumbers instance." ) self._y = y self._parameter_numbers = parameter_numbers y = utils.read_only_property("_y") parameter_numbers = utils.read_only_property("_parameter_numbers") def public_key(self, backend): return backend.load_dsa_public_numbers(self) def __eq__(self, other): if not isinstance(other, DSAPublicNumbers): return NotImplemented return ( self.y == other.y and self.parameter_numbers == other.parameter_numbers ) def __ne__(self, other): return not self == other def __repr__(self): return ( "<DSAPublicNumbers(y={self.y}, " "parameter_numbers={self.parameter_numbers})>".format(self=self) ) class DSAPrivateNumbers(object): def __init__(self, x, public_numbers): if not isinstance(x, six.integer_types): raise TypeError("DSAPrivateNumbers x argument must be an integer.") if not isinstance(public_numbers, DSAPublicNumbers): raise TypeError( "public_numbers must be a DSAPublicNumbers instance." ) self._public_numbers = public_numbers self._x = x x = utils.read_only_property("_x") public_numbers = utils.read_only_property("_public_numbers") def private_key(self, backend): return backend.load_dsa_private_numbers(self) def __eq__(self, other): if not isinstance(other, DSAPrivateNumbers): return NotImplemented return ( self.x == other.x and self.public_numbers == other.public_numbers ) def __ne__(self, other): return not self == other Submit