66 lines
2.1 KiB
C
66 lines
2.1 KiB
C
/*
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* Copyright (C) 2020 Olivier Chéron <olivier.cheron@gmail.com>
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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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* 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 the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef CRYPTONITE_HASH_PREFIX_H
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#define CRYPTONITE_HASH_PREFIX_H
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#include <stdint.h>
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static inline uint32_t constant_time_msb(uint32_t a)
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{
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return 0 - (a >> 31);
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}
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static inline uint32_t constant_time_lt(uint32_t a, uint32_t b)
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{
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return constant_time_msb(a ^ ((a ^ b) | ((a - b) ^ b)));
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}
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static inline uint32_t constant_time_ge(uint32_t a, uint32_t b)
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{
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return ~constant_time_lt(a, b);
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}
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static inline uint32_t constant_time_is_zero(uint32_t a)
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{
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return constant_time_msb(~a & (a - 1));
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}
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static inline uint32_t constant_time_eq(uint32_t a, uint32_t b)
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{
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return constant_time_is_zero(a ^ b);
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}
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static inline uint64_t constant_time_msb_64(uint64_t a)
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{
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return 0 - (a >> 63);
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}
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static inline uint64_t constant_time_lt_64(uint64_t a, uint64_t b)
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{
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return constant_time_msb_64(a ^ ((a ^ b) | ((a - b) ^ b)));
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}
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#endif
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