From 1dac2263372df2b85db5d029a45721fa158a5c9d Mon Sep 17 00:00:00 2001 From: xiubuzhe Date: Sun, 8 Oct 2023 20:59:00 +0800 Subject: first add files --- lib/Crypto/Util/strxor.py | 146 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100644 lib/Crypto/Util/strxor.py (limited to 'lib/Crypto/Util/strxor.py') diff --git a/lib/Crypto/Util/strxor.py b/lib/Crypto/Util/strxor.py new file mode 100644 index 0000000..362db6e --- /dev/null +++ b/lib/Crypto/Util/strxor.py @@ -0,0 +1,146 @@ +# =================================================================== +# +# Copyright (c) 2014, Legrandin +# 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._raw_api import (load_pycryptodome_raw_lib, c_size_t, + create_string_buffer, get_raw_buffer, + c_uint8_ptr, is_writeable_buffer) + +_raw_strxor = load_pycryptodome_raw_lib( + "Crypto.Util._strxor", + """ + void strxor(const uint8_t *in1, + const uint8_t *in2, + uint8_t *out, size_t len); + void strxor_c(const uint8_t *in, + uint8_t c, + uint8_t *out, + size_t len); + """) + + +def strxor(term1, term2, output=None): + """From two byte strings of equal length, + create a third one which is the byte-by-byte XOR of the two. + + Args: + term1 (bytes/bytearray/memoryview): + The first byte string to XOR. + term2 (bytes/bytearray/memoryview): + The second byte string to XOR. + output (bytearray/memoryview): + The location where the result will be written to. + It must have the same length as ``term1`` and ``term2``. + If ``None``, the result is returned. + :Return: + If ``output`` is ``None``, a new byte string with the result. + Otherwise ``None``. + + .. note:: + ``term1`` and ``term2`` must have the same length. + """ + + if len(term1) != len(term2): + raise ValueError("Only byte strings of equal length can be xored") + + if output is None: + result = create_string_buffer(len(term1)) + else: + # Note: output may overlap with either input + result = output + + if not is_writeable_buffer(output): + raise TypeError("output must be a bytearray or a writeable memoryview") + + if len(term1) != len(output): + raise ValueError("output must have the same length as the input" + " (%d bytes)" % len(term1)) + + _raw_strxor.strxor(c_uint8_ptr(term1), + c_uint8_ptr(term2), + c_uint8_ptr(result), + c_size_t(len(term1))) + + if output is None: + return get_raw_buffer(result) + else: + return None + + +def strxor_c(term, c, output=None): + """From a byte string, create a second one of equal length + where each byte is XOR-red with the same value. + + Args: + term(bytes/bytearray/memoryview): + The byte string to XOR. + c (int): + Every byte in the string will be XOR-ed with this value. + It must be between 0 and 255 (included). + output (None or bytearray/memoryview): + The location where the result will be written to. + It must have the same length as ``term``. + If ``None``, the result is returned. + + Return: + If ``output`` is ``None``, a new ``bytes`` string with the result. + Otherwise ``None``. + """ + + if not 0 <= c < 256: + raise ValueError("c must be in range(256)") + + if output is None: + result = create_string_buffer(len(term)) + else: + # Note: output may overlap with either input + result = output + + if not is_writeable_buffer(output): + raise TypeError("output must be a bytearray or a writeable memoryview") + + if len(term) != len(output): + raise ValueError("output must have the same length as the input" + " (%d bytes)" % len(term)) + + _raw_strxor.strxor_c(c_uint8_ptr(term), + c, + c_uint8_ptr(result), + c_size_t(len(term)) + ) + + if output is None: + return get_raw_buffer(result) + else: + return None + + +def _strxor_direct(term1, term2, result): + """Very fast XOR - check conditions!""" + _raw_strxor.strxor(term1, term2, result, c_size_t(len(term1))) -- cgit v1.2.3