Mercurial > dropbear

comparison bn_mp_prime_random_ex.c @ 142:d29b64170cf0 libtommath-orig

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
import of libtommath 0.32
author Matt Johnston <matt@ucc.asn.au>
date Sun, 19 Dec 2004 11:33:56 +0000
parents 86e0b50a9b58
children d8254fc979e9
comparison
equal deleted inserted replaced
19:e1037a1e12e7 142:d29b64170cf0
1 #include <tommath.h>
2 #ifdef BN_MP_PRIME_RANDOM_EX_C
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 * 4 *
3 * LibTomMath is a library that provides multiple-precision 5 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality. 6 * integer arithmetic as well as number theoretic functionality.
5 * 7 *
10 * The library is free for all purposes without any express 12 * The library is free for all purposes without any express
11 * guarantee it works. 13 * guarantee it works.
12 * 14 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org 15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */ 16 */
15 #include <tommath.h>
16 17
17 /* makes a truly random prime of a given size (bits), 18 /* makes a truly random prime of a given size (bits),
18 * 19 *
19 * Flags are as follows: 20 * Flags are as follows:
20 * 21 *
90 /* read it in */ 91 /* read it in */
91 if ((err = mp_read_unsigned_bin(a, tmp, bsize)) != MP_OKAY) { goto error; } 92 if ((err = mp_read_unsigned_bin(a, tmp, bsize)) != MP_OKAY) { goto error; }
92 93
93 /* is it prime? */ 94 /* is it prime? */
94 if ((err = mp_prime_is_prime(a, t, &res)) != MP_OKAY) { goto error; } 95 if ((err = mp_prime_is_prime(a, t, &res)) != MP_OKAY) { goto error; }
96 if (res == MP_NO) {
97 continue;
98 }
95 99
96 if (flags & LTM_PRIME_SAFE) { 100 if (flags & LTM_PRIME_SAFE) {
97 /* see if (a-1)/2 is prime */ 101 /* see if (a-1)/2 is prime */
98 if ((err = mp_sub_d(a, 1, a)) != MP_OKAY) { goto error; } 102 if ((err = mp_sub_d(a, 1, a)) != MP_OKAY) { goto error; }
99 if ((err = mp_div_2(a, a)) != MP_OKAY) { goto error; } 103 if ((err = mp_div_2(a, a)) != MP_OKAY) { goto error; }
114 XFREE(tmp); 118 XFREE(tmp);
115 return err; 119 return err;
116 } 120 }
117 121
118 122
123 #endif