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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
from fractions import gcd
import six
from cryptography import utils
from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
from cryptography.hazmat.backends.interfaces import RSABackend
@six.add_metaclass(abc.ABCMeta)
class RSAPrivateKey(object):
@abc.abstractmethod
def signer(self, padding, algorithm):
"""
Returns an AsymmetricSignatureContext used for signing data.
"""
@abc.abstractmethod
def decrypt(self, ciphertext, padding):
"""
Decrypts the provided ciphertext.
"""
@abc.abstractproperty
def key_size(self):
"""
The bit length of the public modulus.
"""
@abc.abstractmethod
def public_key(self):
"""
The RSAPublicKey associated with this private key.
"""
@six.add_metaclass(abc.ABCMeta)
class RSAPrivateKeyWithSerialization(RSAPrivateKey):
@abc.abstractmethod
def private_numbers(self):
"""
Returns an RSAPrivateNumbers.
"""
@abc.abstractmethod
def private_bytes(self, encoding, format, encryption_algorithm):
"""
Returns the key serialized as bytes.
"""
@six.add_metaclass(abc.ABCMeta)
class RSAPublicKey(object):
@abc.abstractmethod
def verifier(self, signature, padding, algorithm):
"""
Returns an AsymmetricVerificationContext used for verifying signatures.
"""
@abc.abstractmethod
def encrypt(self, plaintext, padding):
"""
Encrypts the given plaintext.
"""
@abc.abstractproperty
def key_size(self):
"""
The bit length of the public modulus.
"""
@abc.abstractmethod
def public_numbers(self):
"""
Returns an RSAPublicNumbers
"""
@abc.abstractmethod
def public_bytes(self, encoding, format):
"""
Returns the key serialized as bytes.
"""
RSAPublicKeyWithSerialization = RSAPublicKey
def generate_private_key(public_exponent, key_size, backend):
if not isinstance(backend, RSABackend):
raise UnsupportedAlgorithm(
"Backend object does not implement RSABackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
_verify_rsa_parameters(public_exponent, key_size)
return backend.generate_rsa_private_key(public_exponent, key_size)
def _verify_rsa_parameters(public_exponent, key_size):
if public_exponent < 3:
raise ValueError("public_exponent must be >= 3.")
if public_exponent & 1 == 0:
raise ValueError("public_exponent must be odd.")
if key_size < 512:
raise ValueError("key_size must be at least 512-bits.")
def _check_private_key_components(p, q, private_exponent, dmp1, dmq1, iqmp,
public_exponent, modulus):
if modulus < 3:
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