diff options
Diffstat (limited to 'src/cryptography/hazmat/primitives/asymmetric/dsa.py')
-rw-r--r-- | src/cryptography/hazmat/primitives/asymmetric/dsa.py | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/cryptography/hazmat/primitives/asymmetric/dsa.py b/src/cryptography/hazmat/primitives/asymmetric/dsa.py new file mode 100644 index 00000000..83e01377 --- /dev/null +++ b/src/cryptography/hazmat/primitives/asymmetric/dsa.py @@ -0,0 +1,108 @@ +# 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 + + +def generate_parameters(key_size, backend): + return backend.generate_dsa_parameters(key_size) + + +def generate_private_key(key_size, backend): + return backend.generate_dsa_private_key_and_parameters(key_size) + + +def _check_dsa_parameters(parameters): + if utils.bit_length(parameters.p) not in [1024, 2048, 3072]: + raise ValueError("p must be exactly 1024, 2048, or 3072 bits long") + if utils.bit_length(parameters.q) not in [160, 256]: + raise ValueError("q must be exactly 160 or 256 bits long") + + if not (1 < parameters.g < parameters.p): + raise ValueError("g, p don't satisfy 1 < g < p.") + + +def _check_dsa_private_numbers(numbers): + parameters = numbers.public_numbers.parameter_numbers + _check_dsa_parameters(parameters) + if numbers.x <= 0 or numbers.x >= parameters.q: + raise ValueError("x must be > 0 and < q.") + + if numbers.public_numbers.y != pow(parameters.g, numbers.x, parameters.p): + raise ValueError("y must be equal to (g ** x % p).") + + +class DSAParameterNumbers(object): + def __init__(self, p, q, g): + if ( + not isinstance(p, six.integer_types) or + not isinstance(q, six.integer_types) or + not isinstance(g, six.integer_types) + ): + raise TypeError( + "DSAParameterNumbers p, q, and g arguments must be integers." + ) + + self._p = p + self._q = q + self._g = g + + p = utils.read_only_property("_p") + q = utils.read_only_property("_q") + g = utils.read_only_property("_g") + + def parameters(self, backend): + return backend.load_dsa_parameter_numbers(self) + + +class DSAPublicNumbers(object): + def __init__(self, y, parameter_numbers): + if not isinstance(y, six.integer_types): + raise TypeError("DSAPublicNumbers y argument must be an integer.") + + if not isinstance(parameter_numbers, DSAParameterNumbers): + raise TypeError( + "parameter_numbers must be a DSAParameterNumbers instance." + ) + + self._y = y + self._parameter_numbers = parameter_numbers + + y = utils.read_only_property("_y") + parameter_numbers = utils.read_only_property("_parameter_numbers") + + def public_key(self, backend): + return backend.load_dsa_public_numbers(self) + + +class DSAPrivateNumbers(object): + def __init__(self, x, public_numbers): + if not isinstance(x, six.integer_types): + raise TypeError("DSAPrivateNumbers x argument must be an integer.") + + if not isinstance(public_numbers, DSAPublicNumbers): + raise TypeError( + "public_numbers must be a DSAPublicNumbers instance." + ) + self._public_numbers = public_numbers + self._x = x + + x = utils.read_only_property("_x") + public_numbers = utils.read_only_property("_public_numbers") + + def private_key(self, backend): + return backend.load_dsa_private_numbers(self) |