1f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#include <tommath.h> 2f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_MP_PRIME_IS_PRIME_C 3f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* LibTomMath, multiple-precision integer library -- Tom St Denis 4f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 5f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * LibTomMath is a library that provides multiple-precision 6f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * integer arithmetic as well as number theoretic functionality. 7f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 8f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The library was designed directly after the MPI library by 9f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Michael Fromberger but has been written from scratch with 10f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * additional optimizations in place. 11f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 12f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The library is free for all purposes without any express 13f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * guarantee it works. 14f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 15f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com 16f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project */ 17f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 18f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* performs a variable number of rounds of Miller-Rabin 19f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 20f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Probability of error after t rounds is no more than 21f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Sets result to 1 if probably prime, 0 otherwise 24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project */ 25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint mp_prime_is_prime (mp_int * a, int t, int *result) 26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{ 27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project mp_int b; 28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int ix, err, res; 29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* default to no */ 31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *result = MP_NO; 32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* valid value of t? */ 34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (t <= 0 || t > PRIME_SIZE) { 35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return MP_VAL; 36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* is the input equal to one of the primes in the table? */ 39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (ix = 0; ix < PRIME_SIZE; ix++) { 40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (mp_cmp_d(a, ltm_prime_tab[ix]) == MP_EQ) { 41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *result = 1; 42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return MP_OKAY; 43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* first perform trial division */ 47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = mp_prime_is_divisible (a, &res)) != MP_OKAY) { 48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* return if it was trivially divisible */ 52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (res == MP_YES) { 53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return MP_OKAY; 54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* now perform the miller-rabin rounds */ 57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = mp_init (&b)) != MP_OKAY) { 58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 61f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (ix = 0; ix < t; ix++) { 62f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* set the prime */ 63f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project mp_set (&b, ltm_prime_tab[ix]); 64f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 65f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = mp_prime_miller_rabin (a, &b, &res)) != MP_OKAY) { 66f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project goto LBL_B; 67f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 68f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 69f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (res == MP_NO) { 70f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project goto LBL_B; 71f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 72f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 73f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 74f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* passed the test */ 75f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *result = MP_YES; 76f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source ProjectLBL_B:mp_clear (&b); 77f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 78f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project} 79f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 80f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 81f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtommath/bn_mp_prime_is_prime.c,v $ */ 82f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.3 $ */ 83f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/03/31 14:18:44 $ */ 84