298 lines
8.2 KiB
Python
298 lines
8.2 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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import abc
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import typing
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from cryptography.hazmat.backends import _get_backend
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from cryptography.hazmat.backends.interfaces import Backend
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from cryptography.hazmat.primitives import _serialization, hashes
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from cryptography.hazmat.primitives.asymmetric import (
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AsymmetricSignatureContext,
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AsymmetricVerificationContext,
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utils as asym_utils,
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)
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class DSAParameters(metaclass=abc.ABCMeta):
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@abc.abstractmethod
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def generate_private_key(self) -> "DSAPrivateKey":
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"""
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Generates and returns a DSAPrivateKey.
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"""
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@abc.abstractmethod
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def parameter_numbers(self) -> "DSAParameterNumbers":
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"""
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Returns a DSAParameterNumbers.
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"""
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DSAParametersWithNumbers = DSAParameters
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class DSAPrivateKey(metaclass=abc.ABCMeta):
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@abc.abstractproperty
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def key_size(self) -> int:
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"""
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The bit length of the prime modulus.
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"""
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@abc.abstractmethod
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def public_key(self) -> "DSAPublicKey":
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"""
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The DSAPublicKey associated with this private key.
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"""
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@abc.abstractmethod
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def parameters(self) -> DSAParameters:
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"""
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The DSAParameters object associated with this private key.
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"""
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@abc.abstractmethod
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def signer(
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self,
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signature_algorithm: hashes.HashAlgorithm,
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) -> AsymmetricSignatureContext:
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"""
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Returns an AsymmetricSignatureContext used for signing data.
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"""
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@abc.abstractmethod
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def sign(
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self,
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data: bytes,
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algorithm: typing.Union[asym_utils.Prehashed, hashes.HashAlgorithm],
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) -> bytes:
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"""
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Signs the data
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"""
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@abc.abstractmethod
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def private_numbers(self) -> "DSAPrivateNumbers":
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"""
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Returns a DSAPrivateNumbers.
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"""
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@abc.abstractmethod
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def private_bytes(
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self,
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encoding: _serialization.Encoding,
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format: _serialization.PrivateFormat,
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encryption_algorithm: _serialization.KeySerializationEncryption,
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) -> bytes:
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"""
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Returns the key serialized as bytes.
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"""
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DSAPrivateKeyWithSerialization = DSAPrivateKey
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class DSAPublicKey(metaclass=abc.ABCMeta):
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@abc.abstractproperty
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def key_size(self) -> int:
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"""
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The bit length of the prime modulus.
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"""
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@abc.abstractmethod
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def parameters(self) -> DSAParameters:
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"""
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The DSAParameters object associated with this public key.
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"""
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@abc.abstractmethod
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def verifier(
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self,
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signature: bytes,
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signature_algorithm: hashes.HashAlgorithm,
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) -> AsymmetricVerificationContext:
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"""
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Returns an AsymmetricVerificationContext used for signing data.
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"""
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@abc.abstractmethod
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def public_numbers(self) -> "DSAPublicNumbers":
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"""
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Returns a DSAPublicNumbers.
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"""
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@abc.abstractmethod
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def public_bytes(
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self,
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encoding: _serialization.Encoding,
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format: _serialization.PublicFormat,
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) -> bytes:
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"""
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Returns the key serialized as bytes.
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"""
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@abc.abstractmethod
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def verify(
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self,
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signature: bytes,
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data: bytes,
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algorithm: typing.Union[asym_utils.Prehashed, hashes.HashAlgorithm],
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) -> None:
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"""
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Verifies the signature of the data.
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"""
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DSAPublicKeyWithSerialization = DSAPublicKey
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class DSAParameterNumbers(object):
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def __init__(self, p: int, q: int, g: int):
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if (
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not isinstance(p, int)
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or not isinstance(q, int)
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or not isinstance(g, int)
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):
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raise TypeError(
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"DSAParameterNumbers p, q, and g arguments must be integers."
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)
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self._p = p
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self._q = q
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self._g = g
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p = property(lambda self: self._p)
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q = property(lambda self: self._q)
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g = property(lambda self: self._g)
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def parameters(
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self, backend: typing.Optional[Backend] = None
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) -> DSAParameters:
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backend = _get_backend(backend)
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return backend.load_dsa_parameter_numbers(self)
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def __eq__(self, other):
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if not isinstance(other, DSAParameterNumbers):
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return NotImplemented
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return self.p == other.p and self.q == other.q and self.g == other.g
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def __ne__(self, other):
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return not self == other
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def __repr__(self):
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return (
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"<DSAParameterNumbers(p={self.p}, q={self.q}, "
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"g={self.g})>".format(self=self)
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)
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class DSAPublicNumbers(object):
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def __init__(self, y: int, parameter_numbers: DSAParameterNumbers):
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if not isinstance(y, int):
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raise TypeError("DSAPublicNumbers y argument must be an integer.")
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if not isinstance(parameter_numbers, DSAParameterNumbers):
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raise TypeError(
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"parameter_numbers must be a DSAParameterNumbers instance."
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)
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self._y = y
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self._parameter_numbers = parameter_numbers
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y = property(lambda self: self._y)
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parameter_numbers = property(lambda self: self._parameter_numbers)
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def public_key(
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self, backend: typing.Optional[Backend] = None
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) -> DSAPublicKey:
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backend = _get_backend(backend)
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return backend.load_dsa_public_numbers(self)
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def __eq__(self, other):
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if not isinstance(other, DSAPublicNumbers):
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return NotImplemented
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return (
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self.y == other.y
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and self.parameter_numbers == other.parameter_numbers
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)
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def __ne__(self, other):
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return not self == other
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def __repr__(self):
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return (
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"<DSAPublicNumbers(y={self.y}, "
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"parameter_numbers={self.parameter_numbers})>".format(self=self)
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)
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class DSAPrivateNumbers(object):
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def __init__(self, x: int, public_numbers: DSAPublicNumbers):
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if not isinstance(x, int):
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raise TypeError("DSAPrivateNumbers x argument must be an integer.")
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if not isinstance(public_numbers, DSAPublicNumbers):
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raise TypeError(
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"public_numbers must be a DSAPublicNumbers instance."
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)
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self._public_numbers = public_numbers
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self._x = x
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x = property(lambda self: self._x)
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public_numbers = property(lambda self: self._public_numbers)
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def private_key(
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self, backend: typing.Optional[Backend] = None
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) -> DSAPrivateKey:
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backend = _get_backend(backend)
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return backend.load_dsa_private_numbers(self)
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def __eq__(self, other):
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if not isinstance(other, DSAPrivateNumbers):
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return NotImplemented
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return (
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self.x == other.x and self.public_numbers == other.public_numbers
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)
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def __ne__(self, other):
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return not self == other
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def generate_parameters(
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key_size: int, backend: typing.Optional[Backend] = None
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) -> DSAParameters:
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backend = _get_backend(backend)
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return backend.generate_dsa_parameters(key_size)
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def generate_private_key(
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key_size: int, backend: typing.Optional[Backend] = None
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) -> DSAPrivateKey:
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backend = _get_backend(backend)
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return backend.generate_dsa_private_key_and_parameters(key_size)
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def _check_dsa_parameters(parameters: DSAParameterNumbers) -> None:
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if parameters.p.bit_length() not in [1024, 2048, 3072, 4096]:
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raise ValueError(
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"p must be exactly 1024, 2048, 3072, or 4096 bits long"
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)
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if parameters.q.bit_length() not in [160, 224, 256]:
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raise ValueError("q must be exactly 160, 224, or 256 bits long")
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if not (1 < parameters.g < parameters.p):
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raise ValueError("g, p don't satisfy 1 < g < p.")
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def _check_dsa_private_numbers(numbers: DSAPrivateNumbers) -> None:
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parameters = numbers.public_numbers.parameter_numbers
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_check_dsa_parameters(parameters)
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if numbers.x <= 0 or numbers.x >= parameters.q:
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raise ValueError("x must be > 0 and < q.")
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if numbers.public_numbers.y != pow(parameters.g, numbers.x, parameters.p):
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raise ValueError("y must be equal to (g ** x % p).")
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