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comparison libtommath/bn_mp_prime_fermat.c @ 1692:1051e4eea25a

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Update LibTomMath to 1.2.0 (#84) * update C files * update other files * update headers * update makefiles * remove mp_set/get_double() * use ltm 1.2.0 API * update ltm_desc * use bundled tommath if system-tommath is too old * XMALLOC etc. were changed to MP_MALLOC etc.
author Steffen Jaeckel <s@jaeckel.eu>
date Tue, 26 May 2020 17:36:47 +0200
parents f52919ffd3b1
children
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1691:2d3745d58843 1692:1051e4eea25a
1 #include "tommath_private.h" 1 #include "tommath_private.h"
2 #ifdef BN_MP_PRIME_FERMAT_C 2 #ifdef BN_MP_PRIME_FERMAT_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
4 * 4 /* SPDX-License-Identifier: Unlicense */
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
7 *
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
11 *
12 * SPDX-License-Identifier: Unlicense
13 */
14 5
15 /* performs one Fermat test. 6 /* performs one Fermat test.
16 * 7 *
17 * If "a" were prime then b**a == b (mod a) since the order of 8 * If "a" were prime then b**a == b (mod a) since the order of
18 * the multiplicative sub-group would be phi(a) = a-1. That means 9 * the multiplicative sub-group would be phi(a) = a-1. That means
19 * it would be the same as b**(a mod (a-1)) == b**1 == b (mod a). 10 * it would be the same as b**(a mod (a-1)) == b**1 == b (mod a).
20 * 11 *
21 * Sets result to 1 if the congruence holds, or zero otherwise. 12 * Sets result to 1 if the congruence holds, or zero otherwise.
22 */ 13 */
23 int mp_prime_fermat(const mp_int *a, const mp_int *b, int *result) 14 mp_err mp_prime_fermat(const mp_int *a, const mp_int *b, mp_bool *result)
24 { 15 {
25 mp_int t; 16 mp_int t;
26 int err; 17 mp_err err;
27 18
28 /* default to composite */ 19 /* default to composite */
29 *result = MP_NO; 20 *result = MP_NO;
30 21
31 /* ensure b > 1 */ 22 /* ensure b > 1 */
52 LBL_T: 43 LBL_T:
53 mp_clear(&t); 44 mp_clear(&t);
54 return err; 45 return err;
55 } 46 }
56 #endif 47 #endif
57
58 /* ref: HEAD -> master, tag: v1.1.0 */
59 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
60 /* commit time: 2019-01-28 20:32:32 +0100 */