diff options
author | Matt Johnston <matt@ucc.asn.au> | 2020-10-15 19:55:15 +0800 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2020-10-15 19:55:15 +0800 |
commit | 0e3e8db5bfca0c579be55e7580a46c593c1384be (patch) | |
tree | 2b1a718f633fb95c1f2d689a591cf9e8642697f3 /libtommath/bn_mp_prime_fermat.c | |
parent | 78e17f6ee9a944430da3e517ee1fe384fd6b275b (diff) | |
parent | 17873e8c922eded2cec86184673a6d110df6403f (diff) |
merge from main
--HG--
branch : fuzz
Diffstat (limited to 'libtommath/bn_mp_prime_fermat.c')
-rw-r--r-- | libtommath/bn_mp_prime_fermat.c | 85 |
1 files changed, 35 insertions, 50 deletions
diff --git a/libtommath/bn_mp_prime_fermat.c b/libtommath/bn_mp_prime_fermat.c index d99feeb..af3e884 100644 --- a/libtommath/bn_mp_prime_fermat.c +++ b/libtommath/bn_mp_prime_fermat.c @@ -1,62 +1,47 @@ -#include <tommath_private.h> +#include "tommath_private.h" #ifdef BN_MP_PRIME_FERMAT_C -/* LibTomMath, multiple-precision integer library -- Tom St Denis - * - * LibTomMath is a library that provides multiple-precision - * integer arithmetic as well as number theoretic functionality. - * - * The library was designed directly after the MPI library by - * Michael Fromberger but has been written from scratch with - * additional optimizations in place. - * - * The library is free for all purposes without any express - * guarantee it works. - * - * Tom St Denis, tstdenis82@gmail.com, http://libtom.org - */ +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ /* performs one Fermat test. - * + * * If "a" were prime then b**a == b (mod a) since the order of * the multiplicative sub-group would be phi(a) = a-1. That means * it would be the same as b**(a mod (a-1)) == b**1 == b (mod a). * * Sets result to 1 if the congruence holds, or zero otherwise. */ -int mp_prime_fermat (mp_int * a, mp_int * b, int *result) +mp_err mp_prime_fermat(const mp_int *a, const mp_int *b, mp_bool *result) { - mp_int t; - int err; - - /* default to composite */ - *result = MP_NO; - - /* ensure b > 1 */ - if (mp_cmp_d(b, 1) != MP_GT) { - return MP_VAL; - } - - /* init t */ - if ((err = mp_init (&t)) != MP_OKAY) { - return err; - } - - /* compute t = b**a mod a */ - if ((err = mp_exptmod (b, a, a, &t)) != MP_OKAY) { - goto LBL_T; - } - - /* is it equal to b? */ - if (mp_cmp (&t, b) == MP_EQ) { - *result = MP_YES; - } - - err = MP_OKAY; -LBL_T:mp_clear (&t); - return err; + mp_int t; + mp_err err; + + /* default to composite */ + *result = MP_NO; + + /* ensure b > 1 */ + if (mp_cmp_d(b, 1uL) != MP_GT) { + return MP_VAL; + } + + /* init t */ + if ((err = mp_init(&t)) != MP_OKAY) { + return err; + } + + /* compute t = b**a mod a */ + if ((err = mp_exptmod(b, a, a, &t)) != MP_OKAY) { + goto LBL_T; + } + + /* is it equal to b? */ + if (mp_cmp(&t, b) == MP_EQ) { + *result = MP_YES; + } + + err = MP_OKAY; +LBL_T: + mp_clear(&t); + return err; } #endif - -/* ref: $Format:%D$ */ -/* git commit: $Format:%H$ */ -/* commit time: $Format:%ai$ */ |