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annotate libtommath/bn_mp_clamp.c @ 1663:c795520269f9

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Fallback for key gen without hard link support (#89) Add a non-atomic fallback for key generation on platforms where link() is not permitted (such as most stock Android installs) or on filesystems without hard link support (such as FAT).
author Matt Robinson <git@nerdoftheherd.com>
date Sat, 14 Mar 2020 14:37:35 +0000
parents f52919ffd3b1
children 1051e4eea25a
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f52919ffd3b1 update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents: 1470
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1 #include "tommath_private.h"
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2 #ifdef BN_MP_CLAMP_C
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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4 *
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5 * LibTomMath is a library that provides multiple-precision
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6 * integer arithmetic as well as number theoretic functionality.
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7 *
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8 * The library was designed directly after the MPI library by
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9 * Michael Fromberger but has been written from scratch with
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10 * additional optimizations in place.
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11 *
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12 * SPDX-License-Identifier: Unlicense
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13 */
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14
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15 /* trim unused digits
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16 *
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17 * This is used to ensure that leading zero digits are
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18 * trimed and the leading "used" digit will be non-zero
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19 * Typically very fast. Also fixes the sign if there
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20 * are no more leading digits
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21 */
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22 void mp_clamp(mp_int *a)
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23 {
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24 /* decrease used while the most significant digit is
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25 * zero.
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26 */
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27 while ((a->used > 0) && (a->dp[a->used - 1] == 0u)) {
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28 --(a->used);
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29 }
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31 /* reset the sign flag if used == 0 */
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32 if (a->used == 0) {
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33 a->sign = MP_ZPOS;
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34 }
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35 }
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36 #endif
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37
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38 /* ref: HEAD -> master, tag: v1.1.0 */
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39 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
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40 /* commit time: 2019-01-28 20:32:32 +0100 */