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# 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
from cryptography.hazmat.backends import _get_backend
def generate_parameters(generator, key_size, backend=None):
backend = _get_backend(backend)
return backend.generate_dh_parameters(generator, key_size)
class DHPrivateNumbers(object):
def __init__(self, x, public_numbers):
if not isinstance(x, six.integer_types):
raise TypeError("x must be an integer.")
if not isinstance(public_numbers, DHPublicNumbers):
raise TypeError(
"public_numbers must be an instance of " "DHPublicNumbers."
)
self._x = x
self._public_numbers = public_numbers
def __eq__(self, other):
if not isinstance(other, DHPrivateNumbers):
return NotImplemented
return (
self._x == other._x
and self._public_numbers == other._public_numbers
)
def __ne__(self, other):
return not self == other
def private_key(self, backend=None):
backend = _get_backend(backend)
return backend.load_dh_private_numbers(self)
public_numbers = utils.read_only_property("_public_numbers")
x = utils.read_only_property("_x")
class DHPublicNumbers(object):
def __init__(self, y, parameter_numbers):
if not isinstance(y, six.integer_types):
raise TypeError("y must be an integer.")
if not isinstance(parameter_numbers, DHParameterNumbers):
raise TypeError(
"parameters must be an instance of DHParameterNumbers."
)
self._y = y
self._parameter_numbers = parameter_numbers
def __eq__(self, other):
if not isinstance(other, DHPublicNumbers):
return NotImplemented
return (
self._y == other._y
and self._parameter_numbers == other._parameter_numbers
)
def __ne__(self, other):
return not self == other
def public_key(self, backend=None):
backend = _get_backend(backend)
return backend.load_dh_public_numbers(self)
y = utils.read_only_property("_y")
parameter_numbers = utils.read_only_property("_parameter_numbers")
class DHParameterNumbers(object):
def __init__(self, p, g, q=None):
if not isinstance(p, six.integer_types) or not isinstance(
g, six.integer_types
):
raise TypeError("p and g must be integers")
if q is not None and not isinstance(q, six.integer_types):
raise TypeError("q must be integer or None")
if g < 2:
raise ValueError("DH generator must be 2 or greater")
self._p = p
self._g = g
self._q = q
def __eq__(self, other):
if not isinstance(other, DHParameterNumbers):
return NotImplemented
return (
self._p == other._p and self._g == other._g and self._q == other._q
)
def __ne__(self, other):
return not self == other
def parameters(self, backend=None):
backend = _get_backend(backend)
return backend.load_dh_parameter_numbers(self)
p = utils.read_only_property("_p")
g = utils.read_only_property("_g")
q = utils.read_only_property("_q")
@six.add_metaclass(abc.ABCMeta)
class DHParameters(object):
@abc.abstractmethod
def generate_private_key(self):
"""
Generates and returns a DHPrivateKey.
"""
@abc.abstractmethod
def parameter_bytes(self, encoding, format):
"""
Returns the parameters serialized as bytes.
"""
@abc.abstractmethod
def parameter_numbers(self):
"""
Returns a DHParameterNumbers.
"""
DHParametersWithSerialization = DHParameters
@six.add_metaclass(abc.ABCMeta)
class DHPrivateKey(object):
@abc.abstractproperty
def key_size(self):
"""
The bit length of the prime modulus.
"""
@abc.abstractmethod
def public_key(self):
"""
The DHPublicKey associated with this private key.
"""
@abc.abstractmethod
def parameters(self):
"""
The DHParameters object associated with this private key.
"""
@abc.abstractmethod
def exchange(self, peer_public_key):
"""
Given peer's DHPublicKey, carry out the key exchange and
return shared key as bytes.
"""
@six.add_metaclass(abc.ABCMeta)
class DHPrivateKeyWithSerialization(DHPrivateKey):
@abc.abstractmethod
def private_numbers(self):
"""
Returns a DHPrivateNumbers.
"""
@abc.abstractmethod
def private_bytes(self, encoding, format, encryption_algorithm):
"""
Returns the key serialized as bytes.
"""
@six.add_metaclass(abc.ABCMeta)
class DHPublicKey(object):
@abc.abstractproperty
def key_size(self):
"""
The bit length of the prime modulus.
"""
@abc.abstractmethod
def parameters(self):
"""
The DHParameters object associated with this public key.
"""
@abc.abstractmethod
def public_numbers(self):
"""
Returns a DHPublicNumbers.
"""
@abc.abstractmethod
def public_bytes(self, encoding, format):
"""
Returns the key serialized as bytes.
"""
DHPublicKeyWithSerialization = DHPublicKey
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