mirror of
http://galexander.org/git/simplesshd.git
synced 2024-11-30 11:18:12 +00:00
84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
#include <tommath.h>
|
|
#ifdef BN_MP_PRIME_IS_PRIME_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, tomstdenis@gmail.com, http://math.libtomcrypt.com
|
|
*/
|
|
|
|
/* performs a variable number of rounds of Miller-Rabin
|
|
*
|
|
* Probability of error after t rounds is no more than
|
|
|
|
*
|
|
* Sets result to 1 if probably prime, 0 otherwise
|
|
*/
|
|
int mp_prime_is_prime (mp_int * a, int t, int *result)
|
|
{
|
|
mp_int b;
|
|
int ix, err, res;
|
|
|
|
/* default to no */
|
|
*result = MP_NO;
|
|
|
|
/* valid value of t? */
|
|
if (t <= 0 || t > PRIME_SIZE) {
|
|
return MP_VAL;
|
|
}
|
|
|
|
/* is the input equal to one of the primes in the table? */
|
|
for (ix = 0; ix < PRIME_SIZE; ix++) {
|
|
if (mp_cmp_d(a, ltm_prime_tab[ix]) == MP_EQ) {
|
|
*result = 1;
|
|
return MP_OKAY;
|
|
}
|
|
}
|
|
|
|
/* first perform trial division */
|
|
if ((err = mp_prime_is_divisible (a, &res)) != MP_OKAY) {
|
|
return err;
|
|
}
|
|
|
|
/* return if it was trivially divisible */
|
|
if (res == MP_YES) {
|
|
return MP_OKAY;
|
|
}
|
|
|
|
/* now perform the miller-rabin rounds */
|
|
if ((err = mp_init (&b)) != MP_OKAY) {
|
|
return err;
|
|
}
|
|
|
|
for (ix = 0; ix < t; ix++) {
|
|
/* set the prime */
|
|
mp_set (&b, ltm_prime_tab[ix]);
|
|
|
|
if ((err = mp_prime_miller_rabin (a, &b, &res)) != MP_OKAY) {
|
|
goto LBL_B;
|
|
}
|
|
|
|
if (res == MP_NO) {
|
|
goto LBL_B;
|
|
}
|
|
}
|
|
|
|
/* passed the test */
|
|
*result = MP_YES;
|
|
LBL_B:mp_clear (&b);
|
|
return err;
|
|
}
|
|
#endif
|
|
|
|
/* $Source: /cvs/libtom/libtommath/bn_mp_prime_is_prime.c,v $ */
|
|
/* $Revision: 1.3 $ */
|
|
/* $Date: 2006/03/31 14:18:44 $ */
|