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Contents
/* Copyright (c) 2016, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include "internal.h"
/* Incomplete-reduction routines; for details on allowed input ranges
* and produced output ranges, see the description in the paper:
* https://cryptojedi.org/papers/#newhope */
static const uint32_t kQInv = 12287; /* -inverse_mod(p,2^18) */
static const uint32_t kRLog = 18;
uint16_t newhope_montgomery_reduce(uint32_t a) {
uint32_t u;
u = (a * kQInv);
u &= ((1 << kRLog) - 1);
u *= PARAM_Q;
a = a + u;
return a >> 18;
}
uint16_t newhope_barrett_reduce(uint16_t a) {
uint32_t u;
u = ((uint32_t)a * 5) >> 16;
u *= PARAM_Q;
a -= u;
return a;
}
Version data entries
33 entries across 33 versions & 2 rubygems