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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.org
*/
#include "tomcrypt.h"
/**
@file rand_prime.c
Generate a random prime, Tom St Denis
*/
#ifdef MPI
struct rng_data {
prng_state *prng;
int wprng;
};
static int rand_prime_helper(unsigned char *dst, int len, void *dat)
{
return (int)prng_descriptor[((struct rng_data *)dat)->wprng].read(dst, len, ((struct rng_data *)dat)->prng);
}
int rand_prime(mp_int *N, long len, prng_state *prng, int wprng)
{
struct rng_data rng;
int type, err;
LTC_ARGCHK(N != NULL);
/* allow sizes between 2 and 256 bytes for a prime size */
if (len < 16 || len > 4096) {
return CRYPT_INVALID_PRIME_SIZE;
}
/* valid PRNG? Better be! */
if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
return err;
}
/* setup our callback data, then world domination! */
rng.prng = prng;
rng.wprng = wprng;
/* get type */
if (len < 0) {
type = LTM_PRIME_BBS;
len = -len;
} else {
type = 0;
}
type |= LTM_PRIME_2MSB_ON;
/* New prime generation makes the code even more cryptoish-insane. Do you know what this means!!!
-- Gir: Yeah, oh wait, er, no.
*/
return mpi_to_ltc_error(mp_prime_random_ex(N, mp_prime_rabin_miller_trials(len), len, type, rand_prime_helper, &rng));
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/misc/mpi/rand_prime.c,v $ */
/* $Revision: 1.3 $ */
/* $Date: 2005/05/05 14:35:59 $ */
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