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Diffstat (limited to 'frozen_deps/Cryptodome/Cipher/_mode_ecb.py')
| -rw-r--r-- | frozen_deps/Cryptodome/Cipher/_mode_ecb.py | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Cipher/_mode_ecb.py b/frozen_deps/Cryptodome/Cipher/_mode_ecb.py new file mode 100644 index 0000000..4c381f7 --- /dev/null +++ b/frozen_deps/Cryptodome/Cipher/_mode_ecb.py @@ -0,0 +1,218 @@ +# -*- coding: utf-8 -*- +# +# Cipher/mode_ecb.py : ECB mode +# +# =================================================================== +# 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. +# =================================================================== + +""" +Electronic Code Book (ECB) mode. +""" + +__all__ = [ 'EcbMode' ] + +from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib, + VoidPointer, create_string_buffer, + get_raw_buffer, SmartPointer, + c_size_t, c_uint8_ptr, + is_writeable_buffer) + +raw_ecb_lib = load_pycryptodome_raw_lib("Cryptodome.Cipher._raw_ecb", """ + int ECB_start_operation(void *cipher, + void **pResult); + int ECB_encrypt(void *ecbState, + const uint8_t *in, + uint8_t *out, + size_t data_len); + int ECB_decrypt(void *ecbState, + const uint8_t *in, + uint8_t *out, + size_t data_len); + int ECB_stop_operation(void *state); + """ + ) + + +class EcbMode(object): + """*Electronic Code Book (ECB)*. + + This is the simplest encryption mode. Each of the plaintext blocks + is directly encrypted into a ciphertext block, independently of + any other block. + + This mode is dangerous because it exposes frequency of symbols + in your plaintext. Other modes (e.g. *CBC*) should be used instead. + + See `NIST SP800-38A`_ , Section 6.1. + + .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf + + :undocumented: __init__ + """ + + def __init__(self, block_cipher): + """Create a new block cipher, configured in ECB mode. + + :Parameters: + block_cipher : C pointer + A smart pointer to the low-level block cipher instance. + """ + + self._state = VoidPointer() + result = raw_ecb_lib.ECB_start_operation(block_cipher.get(), + self._state.address_of()) + if result: + raise ValueError("Error %d while instantiating the ECB mode" + % result) + + # Ensure that object disposal of this Python object will (eventually) + # free the memory allocated by the raw library for the cipher + # mode + self._state = SmartPointer(self._state.get(), + raw_ecb_lib.ECB_stop_operation) + + # Memory allocated for the underlying block cipher is now owned + # by the cipher mode + block_cipher.release() + + def encrypt(self, plaintext, output=None): + """Encrypt data with the key set at initialization. + + The data to encrypt can be broken up in two or + more pieces and `encrypt` can be called multiple times. + + That is, the statement: + + >>> c.encrypt(a) + c.encrypt(b) + + is equivalent to: + + >>> c.encrypt(a+b) + + This function does not add any padding to the plaintext. + + :Parameters: + plaintext : bytes/bytearray/memoryview + The piece of data to encrypt. + The length must be multiple of the cipher block length. + :Keywords: + output : bytearray/memoryview + The location where the ciphertext must be written to. + If ``None``, the ciphertext is returned. + :Return: + If ``output`` is ``None``, the ciphertext is returned as ``bytes``. + Otherwise, ``None``. + """ + + if output is None: + ciphertext = create_string_buffer(len(plaintext)) + else: + ciphertext = output + + if not is_writeable_buffer(output): + raise TypeError("output must be a bytearray or a writeable memoryview") + + if len(plaintext) != len(output): + raise ValueError("output must have the same length as the input" + " (%d bytes)" % len(plaintext)) + + result = raw_ecb_lib.ECB_encrypt(self._state.get(), + c_uint8_ptr(plaintext), + c_uint8_ptr(ciphertext), + c_size_t(len(plaintext))) + if result: + if result == 3: + raise ValueError("Data must be aligned to block boundary in ECB mode") + raise ValueError("Error %d while encrypting in ECB mode" % result) + + if output is None: + return get_raw_buffer(ciphertext) + else: + return None + + def decrypt(self, ciphertext, output=None): + """Decrypt data with the key set at initialization. + + The data to decrypt can be broken up in two or + more pieces and `decrypt` can be called multiple times. + + That is, the statement: + + >>> c.decrypt(a) + c.decrypt(b) + + is equivalent to: + + >>> c.decrypt(a+b) + + This function does not remove any padding from the plaintext. + + :Parameters: + ciphertext : bytes/bytearray/memoryview + The piece of data to decrypt. + The length must be multiple of the cipher block length. + :Keywords: + output : bytearray/memoryview + The location where the plaintext must be written to. + If ``None``, the plaintext is returned. + :Return: + If ``output`` is ``None``, the plaintext is returned as ``bytes``. + Otherwise, ``None``. + """ + + if output is None: + plaintext = create_string_buffer(len(ciphertext)) + else: + plaintext = output + + if not is_writeable_buffer(output): + raise TypeError("output must be a bytearray or a writeable memoryview") + + if len(ciphertext) != len(output): + raise ValueError("output must have the same length as the input" + " (%d bytes)" % len(plaintext)) + + result = raw_ecb_lib.ECB_decrypt(self._state.get(), + c_uint8_ptr(ciphertext), + c_uint8_ptr(plaintext), + c_size_t(len(ciphertext))) + if result: + if result == 3: + raise ValueError("Data must be aligned to block boundary in ECB mode") + raise ValueError("Error %d while decrypting in ECB mode" % result) + + if output is None: + return get_raw_buffer(plaintext) + else: + return None + + +def _create_ecb_cipher(factory, **kwargs): + """Instantiate a cipher object that performs ECB encryption/decryption. + + :Parameters: + factory : module + The underlying block cipher, a module from ``Cryptodome.Cipher``. + + All keywords are passed to the underlying block cipher. + See the relevant documentation for details (at least ``key`` will need + to be present""" + + cipher_state = factory._create_base_cipher(kwargs) + if kwargs: + raise TypeError("Unknown parameters for ECB: %s" % str(kwargs)) + return EcbMode(cipher_state) |