# =================================================================== # # 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)