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Diffstat (limited to 'frozen_deps/Cryptodome/Hash/cSHAKE128.py')
-rw-r--r-- | frozen_deps/Cryptodome/Hash/cSHAKE128.py | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Hash/cSHAKE128.py b/frozen_deps/Cryptodome/Hash/cSHAKE128.py new file mode 100644 index 0000000..7c2f30a --- /dev/null +++ b/frozen_deps/Cryptodome/Hash/cSHAKE128.py @@ -0,0 +1,187 @@ +# =================================================================== +# +# Copyright (c) 2021, Legrandin <[email protected]> +# 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 Cryptodome.Util.py3compat import bchr + +from Cryptodome.Util._raw_api import (VoidPointer, SmartPointer, + create_string_buffer, + get_raw_buffer, c_size_t, + c_uint8_ptr, c_ubyte) + +from Cryptodome.Util.number import long_to_bytes + +from Cryptodome.Hash.keccak import _raw_keccak_lib + + +def _left_encode(x): + """Left encode function as defined in NIST SP 800-185""" + + assert (x < (1 << 2040) and x >= 0) + + # Get number of bytes needed to represent this integer. + num = 1 if x == 0 else (x.bit_length() + 7) // 8 + + return bchr(num) + long_to_bytes(x) + + +def _right_encode(x): + """Right encode function as defined in NIST SP 800-185""" + + assert (x < (1 << 2040) and x >= 0) + + # Get number of bytes needed to represent this integer. + num = 1 if x == 0 else (x.bit_length() + 7) // 8 + + return long_to_bytes(x) + bchr(num) + + +def _encode_str(x): + """Encode string function as defined in NIST SP 800-185""" + + bitlen = len(x) * 8 + if bitlen >= (1 << 2040): + raise ValueError("String too large to encode in cSHAKE") + + return _left_encode(bitlen) + x + + +def _bytepad(x, length): + """Zero pad byte string as defined in NIST SP 800-185""" + + to_pad = _left_encode(length) + x + + # Note: this implementation works with byte aligned strings, + # hence no additional bit padding is needed at this point. + npad = (length - len(to_pad) % length) % length + + return to_pad + b'\x00' * npad + + +class cSHAKE_XOF(object): + """A cSHAKE hash object. + Do not instantiate directly. + Use the :func:`new` function. + """ + + def __init__(self, data, custom, capacity, function): + state = VoidPointer() + + if custom or function: + prefix_unpad = _encode_str(function) + _encode_str(custom) + prefix = _bytepad(prefix_unpad, (1600 - capacity)//8) + self._padding = 0x04 + else: + prefix = None + self._padding = 0x1F # for SHAKE + + result = _raw_keccak_lib.keccak_init(state.address_of(), + c_size_t(capacity//8), + c_ubyte(24)) + if result: + raise ValueError("Error %d while instantiating cSHAKE" + % result) + self._state = SmartPointer(state.get(), + _raw_keccak_lib.keccak_destroy) + self._is_squeezing = False + + if prefix: + self.update(prefix) + + 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 %s state" + % (result, self.name)) + 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 %s" + % (result, self.name)) + + return get_raw_buffer(bfr) + + +def _new(data, custom, function): + # Use Keccak[256] + return cSHAKE_XOF(data, custom, 256, function) + + +def new(data=None, custom=None): + """Return a fresh instance of a cSHAKE128 object. + + Args: + data (bytes/bytearray/memoryview): + Optional. + The very first chunk of the message to hash. + It is equivalent to an early call to :meth:`update`. + custom (bytes): + Optional. + A customization bytestring (``S`` in SP 800-185). + + :Return: A :class:`cSHAKE_XOF` object + """ + + # Use Keccak[256] + return cSHAKE_XOF(data, custom, 256, b'') |