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Diffstat (limited to 'frozen_deps/Cryptodome/Cipher/CAST.py')
| -rw-r--r-- | frozen_deps/Cryptodome/Cipher/CAST.py | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Cipher/CAST.py b/frozen_deps/Cryptodome/Cipher/CAST.py new file mode 100644 index 0000000..84eb88e --- /dev/null +++ b/frozen_deps/Cryptodome/Cipher/CAST.py @@ -0,0 +1,159 @@ +# -*- coding: utf-8 -*- +# +# Cipher/CAST.py : CAST +# +# =================================================================== +# The contents of this file are dedicated to the public domain. To +# the extent that dedication to the public domain is not available, +# everyone is granted a worldwide, perpetual, royalty-free, +# non-exclusive license to exercise all rights associated with the +# contents of this file for any purpose whatsoever. +# No rights are reserved. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS +# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN +# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +# SOFTWARE. +# =================================================================== +""" +Module's constants for the modes of operation supported with CAST: + +:var MODE_ECB: :ref:`Electronic Code Book (ECB) <ecb_mode>` +:var MODE_CBC: :ref:`Cipher-Block Chaining (CBC) <cbc_mode>` +:var MODE_CFB: :ref:`Cipher FeedBack (CFB) <cfb_mode>` +:var MODE_OFB: :ref:`Output FeedBack (OFB) <ofb_mode>` +:var MODE_CTR: :ref:`CounTer Mode (CTR) <ctr_mode>` +:var MODE_OPENPGP: :ref:`OpenPGP Mode <openpgp_mode>` +:var MODE_EAX: :ref:`EAX Mode <eax_mode>` +""" + +import sys + +from Cryptodome.Cipher import _create_cipher +from Cryptodome.Util.py3compat import byte_string +from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib, + VoidPointer, SmartPointer, + c_size_t, c_uint8_ptr) + +_raw_cast_lib = load_pycryptodome_raw_lib( + "Cryptodome.Cipher._raw_cast", + """ + int CAST_start_operation(const uint8_t key[], + size_t key_len, + void **pResult); + int CAST_encrypt(const void *state, + const uint8_t *in, + uint8_t *out, + size_t data_len); + int CAST_decrypt(const void *state, + const uint8_t *in, + uint8_t *out, + size_t data_len); + int CAST_stop_operation(void *state); + """) + + +def _create_base_cipher(dict_parameters): + """This method instantiates and returns a handle to a low-level + base cipher. It will absorb named parameters in the process.""" + + try: + key = dict_parameters.pop("key") + except KeyError: + raise TypeError("Missing 'key' parameter") + + if len(key) not in key_size: + raise ValueError("Incorrect CAST key length (%d bytes)" % len(key)) + + start_operation = _raw_cast_lib.CAST_start_operation + stop_operation = _raw_cast_lib.CAST_stop_operation + + cipher = VoidPointer() + result = start_operation(c_uint8_ptr(key), + c_size_t(len(key)), + cipher.address_of()) + if result: + raise ValueError("Error %X while instantiating the CAST cipher" + % result) + + return SmartPointer(cipher.get(), stop_operation) + + +def new(key, mode, *args, **kwargs): + """Create a new CAST cipher + + :param key: + The secret key to use in the symmetric cipher. + Its length can vary from 5 to 16 bytes. + :type key: bytes, bytearray, memoryview + + :param mode: + The chaining mode to use for encryption or decryption. + :type mode: One of the supported ``MODE_*`` constants + + :Keyword Arguments: + * **iv** (*bytes*, *bytearray*, *memoryview*) -- + (Only applicable for ``MODE_CBC``, ``MODE_CFB``, ``MODE_OFB``, + and ``MODE_OPENPGP`` modes). + + The initialization vector to use for encryption or decryption. + + For ``MODE_CBC``, ``MODE_CFB``, and ``MODE_OFB`` it must be 8 bytes long. + + For ``MODE_OPENPGP`` mode only, + it must be 8 bytes long for encryption + and 10 bytes for decryption (in the latter case, it is + actually the *encrypted* IV which was prefixed to the ciphertext). + + If not provided, a random byte string is generated (you must then + read its value with the :attr:`iv` attribute). + + * **nonce** (*bytes*, *bytearray*, *memoryview*) -- + (Only applicable for ``MODE_EAX`` and ``MODE_CTR``). + + A value that must never be reused for any other encryption done + with this key. + + For ``MODE_EAX`` there are no + restrictions on its length (recommended: **16** bytes). + + For ``MODE_CTR``, its length must be in the range **[0..7]**. + + If not provided for ``MODE_EAX``, a random byte string is generated (you + can read it back via the ``nonce`` attribute). + + * **segment_size** (*integer*) -- + (Only ``MODE_CFB``).The number of **bits** the plaintext and ciphertext + are segmented in. It must be a multiple of 8. + If not specified, it will be assumed to be 8. + + * **mac_len** : (*integer*) -- + (Only ``MODE_EAX``) + Length of the authentication tag, in bytes. + It must be no longer than 8 (default). + + * **initial_value** : (*integer*) -- + (Only ``MODE_CTR``). The initial value for the counter within + the counter block. By default it is **0**. + + :Return: a CAST object, of the applicable mode. + """ + + return _create_cipher(sys.modules[__name__], key, mode, *args, **kwargs) + +MODE_ECB = 1 +MODE_CBC = 2 +MODE_CFB = 3 +MODE_OFB = 5 +MODE_CTR = 6 +MODE_OPENPGP = 7 +MODE_EAX = 9 + +# Size of a data block (in bytes) +block_size = 8 +# Size of a key (in bytes) +key_size = range(5, 16 + 1) |