129 lines
4.7 KiB
Python
129 lines
4.7 KiB
Python
# ===================================================================
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#
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# Copyright (c) 2015, Legrandin <helderijs@gmail.com>
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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# ===================================================================
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from Cryptodome.Util.py3compat import bord
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from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib,
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VoidPointer, SmartPointer,
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create_string_buffer,
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get_raw_buffer, c_size_t,
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c_uint8_ptr, c_ubyte)
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from Cryptodome.Hash.keccak import _raw_keccak_lib
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class SHAKE128_XOF(object):
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"""A SHAKE128 hash object.
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Do not instantiate directly.
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Use the :func:`new` function.
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:ivar oid: ASN.1 Object ID
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:vartype oid: string
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"""
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# ASN.1 Object ID
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oid = "2.16.840.1.101.3.4.2.11"
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def __init__(self, data=None):
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state = VoidPointer()
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result = _raw_keccak_lib.keccak_init(state.address_of(),
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c_size_t(32),
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c_ubyte(24))
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if result:
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raise ValueError("Error %d while instantiating SHAKE128"
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% result)
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self._state = SmartPointer(state.get(),
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_raw_keccak_lib.keccak_destroy)
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self._is_squeezing = False
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self._padding = 0x1F
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if data:
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self.update(data)
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def update(self, data):
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"""Continue hashing of a message by consuming the next chunk of data.
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Args:
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data (byte string/byte array/memoryview): The next chunk of the message being hashed.
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"""
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if self._is_squeezing:
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raise TypeError("You cannot call 'update' after the first 'read'")
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result = _raw_keccak_lib.keccak_absorb(self._state.get(),
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c_uint8_ptr(data),
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c_size_t(len(data)))
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if result:
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raise ValueError("Error %d while updating SHAKE128 state"
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% result)
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return self
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def read(self, length):
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"""
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Compute the next piece of XOF output.
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.. note::
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You cannot use :meth:`update` anymore after the first call to
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:meth:`read`.
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Args:
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length (integer): the amount of bytes this method must return
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:return: the next piece of XOF output (of the given length)
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:rtype: byte string
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"""
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self._is_squeezing = True
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bfr = create_string_buffer(length)
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result = _raw_keccak_lib.keccak_squeeze(self._state.get(),
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bfr,
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c_size_t(length),
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c_ubyte(self._padding))
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if result:
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raise ValueError("Error %d while extracting from SHAKE128"
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% result)
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return get_raw_buffer(bfr)
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def new(self, data=None):
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return type(self)(data=data)
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def new(data=None):
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"""Return a fresh instance of a SHAKE128 object.
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Args:
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data (bytes/bytearray/memoryview):
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The very first chunk of the message to hash.
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It is equivalent to an early call to :meth:`update`.
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Optional.
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:Return: A :class:`SHAKE128_XOF` object
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"""
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return SHAKE128_XOF(data=data)
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