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comparison libtommath/bn_mp_prime_fermat.c @ 1655:f52919ffd3b1

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update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79) * make key-generation compliant to FIPS 186.4 * fix includes in tommath_class.h * update fuzzcorpus instead of error-out * fixup fuzzing make-targets * update Makefile.in * apply necessary patches to ltm sources * clean-up not required ltm files * update to vanilla ltm 1.1.0 this already only contains the required files * remove set/get double
author Steffen Jaeckel <s_jaeckel@gmx.de>
date Mon, 16 Sep 2019 15:50:38 +0200
parents 8bba51a55704
children 1051e4eea25a
comparison
equal deleted inserted replaced
1654:cc0fc5131c5c 1655:f52919ffd3b1
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 *
5 * LibTomMath is a library that provides multiple-precision 5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality. 6 * integer arithmetic as well as number theoretic functionality.
7 * 7 *
8 * The library was designed directly after the MPI library by 8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with 9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place. 10 * additional optimizations in place.
11 * 11 *
12 * The library is free for all purposes without any express 12 * SPDX-License-Identifier: Unlicense
13 * guarantee it works.
14 *
15 * Tom St Denis, [email protected], http://libtom.org
16 */ 13 */
17 14
18 /* performs one Fermat test. 15 /* performs one Fermat test.
19 * 16 *
20 * If "a" were prime then b**a == b (mod a) since the order of 17 * If "a" were prime then b**a == b (mod a) since the order of
21 * the multiplicative sub-group would be phi(a) = a-1. That means 18 * the multiplicative sub-group would be phi(a) = a-1. That means
22 * it would be the same as b**(a mod (a-1)) == b**1 == b (mod a). 19 * it would be the same as b**(a mod (a-1)) == b**1 == b (mod a).
23 * 20 *
24 * Sets result to 1 if the congruence holds, or zero otherwise. 21 * Sets result to 1 if the congruence holds, or zero otherwise.
25 */ 22 */
26 int mp_prime_fermat (mp_int * a, mp_int * b, int *result) 23 int mp_prime_fermat(const mp_int *a, const mp_int *b, int *result)
27 { 24 {
28 mp_int t; 25 mp_int t;
29 int err; 26 int err;
30 27
31 /* default to composite */ 28 /* default to composite */
32 *result = MP_NO; 29 *result = MP_NO;
33 30
34 /* ensure b > 1 */ 31 /* ensure b > 1 */
35 if (mp_cmp_d(b, 1) != MP_GT) { 32 if (mp_cmp_d(b, 1uL) != MP_GT) {
36 return MP_VAL; 33 return MP_VAL;
37 } 34 }
38 35
39 /* init t */ 36 /* init t */
40 if ((err = mp_init (&t)) != MP_OKAY) { 37 if ((err = mp_init(&t)) != MP_OKAY) {
41 return err; 38 return err;
42 } 39 }
43 40
44 /* compute t = b**a mod a */ 41 /* compute t = b**a mod a */
45 if ((err = mp_exptmod (b, a, a, &t)) != MP_OKAY) { 42 if ((err = mp_exptmod(b, a, a, &t)) != MP_OKAY) {
46 goto LBL_T; 43 goto LBL_T;
47 } 44 }
48 45
49 /* is it equal to b? */ 46 /* is it equal to b? */
50 if (mp_cmp (&t, b) == MP_EQ) { 47 if (mp_cmp(&t, b) == MP_EQ) {
51 *result = MP_YES; 48 *result = MP_YES;
52 } 49 }
53 50
54 err = MP_OKAY; 51 err = MP_OKAY;
55 LBL_T:mp_clear (&t); 52 LBL_T:
56 return err; 53 mp_clear(&t);
54 return err;
57 } 55 }
58 #endif 56 #endif
59 57
60 /* ref: $Format:%D$ */ 58 /* ref: HEAD -> master, tag: v1.1.0 */
61 /* git commit: $Format:%H$ */ 59 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
62 /* commit time: $Format:%ai$ */ 60 /* commit time: 2019-01-28 20:32:32 +0100 */