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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import, division, print_function
import six
from cryptography import utils
from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
from cryptography.hazmat.backends.interfaces import RSABackend
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:
raise ValueError("modulus must be >= 3.")
if p >= modulus:
raise ValueError("p must be < modulus.")
if q >= modulus:
raise ValueError("q must be < modulus.")
if dmp1 >= modulus:
raise ValueError("dmp1 must be < modulus.")
if dmq1 >= modulus:
raise ValueError("dmq1 must be < modulus.")
if iqmp >= modulus:
raise ValueError("iqmp must be < modulus.")
if private_exponent >= modulus:
raise ValueError("private_exponent must be < modulus.")
if public_exponent < 3 or public_exponent >= modulus:
raise ValueError("public_exponent must be >= 3 and < modulus.")
if public_exponent & 1 == 0:
raise ValueError("public_exponent must be odd.")
if dmp1 & 1 == 0:
raise ValueError("dmp1 must be odd.")
if dmq1 & 1 == 0:
raise ValueError("dmq1 must be odd.")
if p * q != modulus:
raise ValueError("p*q must equal modulus.")
def _check_public_key_components(e, n):
if n < 3:
raise ValueError("n must be >= 3.")
if e < 3 or e >= n:
raise ValueError("e must be >= 3 and < n.")
if e & 1 == 0:
raise ValueError("e must be odd.")
def _modinv(e, m):
"""
Modular Multiplicative Inverse. Returns x such that: (x*e) mod m == 1
"""
x1, y1, x2, y2 = 1, 0, 0, 1
a, b = e, m
while b > 0:
q, r = divmod(a, b)
xn, yn = x1 - q * x2, y1 - q * y2
a, b, x1, y1, x2, y2 = b, r, x2, y2, xn, yn
return x1 % m
def rsa_crt_iqmp(p, q):
"""
Compute the CRT (q ** -1) % p value from RSA primes p and q.
"""
return _modinv(q, p)
def rsa_crt_dmp1(private_exponent, p):
"""
Compute the CRT private_exponent % (p - 1) value from the RSA
private_exponent and p.
"""
return private_exponent % (p - 1)
def rsa_crt_dmq1(private_exponent, q):
"""
Compute the CRT private_exponent % (q - 1) value from the RSA
private_exponent and q.
"""
return private_exponent % (q - 1)
class RSAPrivateNumbers(object):
def __init__(self, p, q, d, dmp1, dmq1, iqmp,
public_numbers):
if (
not isinstance(p, six.integer_types) or
not isinstance(q, six.integer_types) or
not isinstance(d, six.integer_types) or
not isinstance(dmp1, six.integer_types) or
not isinstance(dmq1, six.integer_types) or
not isinstance(iqmp, six.integer_types)
):
raise TypeError(
"RSAPrivateNumbers p, q, d, dmp1, dmq1, iqmp arguments must"
" all be an integers."
)
if not isinstance(public_numbers, RSAPublicNumbers):
raise TypeError(
"RSAPrivateNumbers public_numbers must be an RSAPublicNumbers"
" instance."
)
self._p = p
self._q = q
self._d = d
self._dmp1 = dmp1
self._dmq1 = dmq1
self._iqmp = iqmp
self._public_numbers = public_numbers
p = utils.read_only_property("_p")
q = utils.read_only_property("_q")
d = utils.read_only_property("_d")
dmp1 = utils.read_only_property("_dmp1")
dmq1 = utils.read_only_property("_dmq1")
iqmp = utils.read_only_property("_iqmp")
public_numbers = utils.read_only_property("_public_numbers")
def private_key(self, backend):
return backend.load_rsa_private_numbers(self)
class RSAPublicNumbers(object):
def __init__(self, e, n):
if (
not isinstance(e, six.integer_types) or
not isinstance(n, six.integer_types)
):
raise TypeError("RSAPublicNumbers arguments must be integers.")
self._e = e
self._n = n
e = utils.read_only_property("_e")
n = utils.read_only_property("_n")
def public_key(self, backend):
return backend.load_rsa_public_numbers(self)
def __repr__(self):
return "<RSAPublicNumbers(e={0}, n={1})>".format(self._e, self._n)
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