240 lines
6.4 KiB
Python
240 lines
6.4 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
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_MIN_MODULUS_SIZE = 512
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def generate_parameters(
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generator: int, key_size: int, backend: typing.Optional[Backend] = None
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) -> "DHParameters":
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backend = _get_backend(backend)
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return backend.generate_dh_parameters(generator, key_size)
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class DHParameterNumbers(object):
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def __init__(self, p: int, g: int, q: typing.Optional[int] = None) -> None:
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if not isinstance(p, int) or not isinstance(g, int):
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raise TypeError("p and g must be integers")
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if q is not None and not isinstance(q, int):
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raise TypeError("q must be integer or None")
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if g < 2:
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raise ValueError("DH generator must be 2 or greater")
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if p.bit_length() < _MIN_MODULUS_SIZE:
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raise ValueError(
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"p (modulus) must be at least {}-bit".format(_MIN_MODULUS_SIZE)
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)
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self._p = p
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self._g = g
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self._q = q
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def __eq__(self, other):
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if not isinstance(other, DHParameterNumbers):
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return NotImplemented
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return (
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self._p == other._p and self._g == other._g and self._q == other._q
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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 parameters(
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self, backend: typing.Optional[Backend] = None
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) -> "DHParameters":
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backend = _get_backend(backend)
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return backend.load_dh_parameter_numbers(self)
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p = property(lambda self: self._p)
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g = property(lambda self: self._g)
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q = property(lambda self: self._q)
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class DHPublicNumbers(object):
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def __init__(self, y: int, parameter_numbers: DHParameterNumbers) -> None:
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if not isinstance(y, int):
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raise TypeError("y must be an integer.")
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if not isinstance(parameter_numbers, DHParameterNumbers):
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raise TypeError(
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"parameters must be an instance of DHParameterNumbers."
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)
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self._y = y
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self._parameter_numbers = parameter_numbers
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def __eq__(self, other):
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if not isinstance(other, DHPublicNumbers):
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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 public_key(
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self, backend: typing.Optional[Backend] = None
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) -> "DHPublicKey":
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backend = _get_backend(backend)
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return backend.load_dh_public_numbers(self)
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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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class DHPrivateNumbers(object):
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def __init__(self, x: int, public_numbers: DHPublicNumbers) -> None:
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if not isinstance(x, int):
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raise TypeError("x must be an integer.")
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if not isinstance(public_numbers, DHPublicNumbers):
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raise TypeError(
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"public_numbers must be an instance of " "DHPublicNumbers."
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)
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self._x = x
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self._public_numbers = public_numbers
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def __eq__(self, other):
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if not isinstance(other, DHPrivateNumbers):
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return NotImplemented
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return (
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self._x == other._x
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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 private_key(
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self, backend: typing.Optional[Backend] = None
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) -> "DHPrivateKey":
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backend = _get_backend(backend)
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return backend.load_dh_private_numbers(self)
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public_numbers = property(lambda self: self._public_numbers)
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x = property(lambda self: self._x)
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class DHParameters(metaclass=abc.ABCMeta):
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@abc.abstractmethod
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def generate_private_key(self) -> "DHPrivateKey":
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"""
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Generates and returns a DHPrivateKey.
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"""
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@abc.abstractmethod
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def parameter_bytes(
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self,
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encoding: "serialization.Encoding",
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format: "serialization.ParameterFormat",
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) -> bytes:
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"""
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Returns the parameters serialized as bytes.
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"""
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@abc.abstractmethod
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def parameter_numbers(self) -> DHParameterNumbers:
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"""
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Returns a DHParameterNumbers.
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"""
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DHParametersWithSerialization = DHParameters
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class DHPublicKey(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) -> DHParameters:
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"""
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The DHParameters object associated with this public key.
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"""
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@abc.abstractmethod
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def public_numbers(self) -> DHPublicNumbers:
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"""
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Returns a DHPublicNumbers.
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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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DHPublicKeyWithSerialization = DHPublicKey
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class DHPrivateKey(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) -> DHPublicKey:
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"""
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The DHPublicKey associated with this private key.
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"""
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@abc.abstractmethod
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def parameters(self) -> DHParameters:
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"""
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The DHParameters object associated with this private key.
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"""
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@abc.abstractmethod
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def exchange(self, peer_public_key: DHPublicKey) -> bytes:
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"""
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Given peer's DHPublicKey, carry out the key exchange and
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return shared key as bytes.
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"""
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@abc.abstractmethod
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def private_numbers(self) -> DHPrivateNumbers:
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"""
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Returns a DHPrivateNumbers.
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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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DHPrivateKeyWithSerialization = DHPrivateKey
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