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| # =================================================================== | |
| # | |
| # Copyright (c) 2015, Legrandin <helderijs@gmail.com> | |
| # All rights reserved. | |
| # | |
| # Redistribution and use in source and binary forms, with or without | |
| # modification, are permitted provided that the following conditions | |
| # are met: | |
| # | |
| # 1. Redistributions of source code must retain the above copyright | |
| # notice, this list of conditions and the following disclaimer. | |
| # 2. Redistributions in binary form must reproduce the above copyright | |
| # notice, this list of conditions and the following disclaimer in | |
| # the documentation and/or other materials provided with the | |
| # distribution. | |
| # | |
| # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | |
| # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | |
| # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| # POSSIBILITY OF SUCH DAMAGE. | |
| # =================================================================== | |
| from Crypto.Util.py3compat import bord | |
| from Crypto.Util._raw_api import (load_pycryptodome_raw_lib, | |
| VoidPointer, SmartPointer, | |
| create_string_buffer, | |
| get_raw_buffer, c_size_t, | |
| c_uint8_ptr, c_ubyte) | |
| from Crypto.Hash.keccak import _raw_keccak_lib | |
| class SHAKE256_XOF(object): | |
| """A SHAKE256 hash object. | |
| Do not instantiate directly. | |
| Use the :func:`new` function. | |
| :ivar oid: ASN.1 Object ID | |
| :vartype oid: string | |
| """ | |
| # ASN.1 Object ID | |
| oid = "2.16.840.1.101.3.4.2.12" | |
| def __init__(self, data=None): | |
| state = VoidPointer() | |
| result = _raw_keccak_lib.keccak_init(state.address_of(), | |
| c_size_t(64), | |
| c_ubyte(24)) | |
| if result: | |
| raise ValueError("Error %d while instantiating SHAKE256" | |
| % result) | |
| self._state = SmartPointer(state.get(), | |
| _raw_keccak_lib.keccak_destroy) | |
| self._is_squeezing = False | |
| self._padding = 0x1F | |
| if data: | |
| self.update(data) | |
| def update(self, data): | |
| """Continue hashing of a message by consuming the next chunk of data. | |
| Args: | |
| data (byte string/byte array/memoryview): The next chunk of the message being hashed. | |
| """ | |
| if self._is_squeezing: | |
| raise TypeError("You cannot call 'update' after the first 'read'") | |
| result = _raw_keccak_lib.keccak_absorb(self._state.get(), | |
| c_uint8_ptr(data), | |
| c_size_t(len(data))) | |
| if result: | |
| raise ValueError("Error %d while updating SHAKE256 state" | |
| % result) | |
| return self | |
| def read(self, length): | |
| """ | |
| Compute the next piece of XOF output. | |
| .. note:: | |
| You cannot use :meth:`update` anymore after the first call to | |
| :meth:`read`. | |
| Args: | |
| length (integer): the amount of bytes this method must return | |
| :return: the next piece of XOF output (of the given length) | |
| :rtype: byte string | |
| """ | |
| self._is_squeezing = True | |
| bfr = create_string_buffer(length) | |
| result = _raw_keccak_lib.keccak_squeeze(self._state.get(), | |
| bfr, | |
| c_size_t(length), | |
| c_ubyte(self._padding)) | |
| if result: | |
| raise ValueError("Error %d while extracting from SHAKE256" | |
| % result) | |
| return get_raw_buffer(bfr) | |
| def new(self, data=None): | |
| return type(self)(data=data) | |
| def new(data=None): | |
| """Return a fresh instance of a SHAKE256 object. | |
| Args: | |
| data (bytes/bytearray/memoryview): | |
| The very first chunk of the message to hash. | |
| It is equivalent to an early call to :meth:`update`. | |
| Optional. | |
| :Return: A :class:`SHAKE256_XOF` object | |
| """ | |
| return SHAKE256_XOF(data=data) | |