annotate rand_prime.c @ 3:7faae8f46238 libtomcrypt-orig

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author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:41 +0000
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children 6362d3854bb4
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
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2 *
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3 * LibTomCrypt is a library that provides various cryptographic
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4 * algorithms in a highly modular and flexible manner.
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5 *
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6 * The library is free for all purposes without any express
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7 * guarantee it works.
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8 *
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9 * Tom St Denis, [email protected], http://libtomcrypt.org
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10 */
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11 #include "mycrypt.h"
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12
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13 #ifdef MPI
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14
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15 struct rng_data {
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16 prng_state *prng;
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17 int wprng;
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18 };
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19
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20 static int rand_prime_helper(unsigned char *dst, int len, void *dat)
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21 {
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22 return (int)prng_descriptor[((struct rng_data *)dat)->wprng].read(dst, len, ((struct rng_data *)dat)->prng);
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23 }
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24
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25 int rand_prime(mp_int *N, long len, prng_state *prng, int wprng)
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26 {
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27 struct rng_data rng;
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28 int type, err;
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29
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30 _ARGCHK(N != NULL);
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31
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32 /* allow sizes between 2 and 256 bytes for a prime size */
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33 if (len < 16 || len > 4096) {
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34 return CRYPT_INVALID_PRIME_SIZE;
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35 }
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36
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37 /* valid PRNG? Better be! */
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38 if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
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39 return err;
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40 }
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41
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42 /* setup our callback data, then world domination! */
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43 rng.prng = prng;
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44 rng.wprng = wprng;
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45
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46 /* get type */
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47 if (len < 0) {
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48 type = LTM_PRIME_BBS;
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49 len = -len;
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50 } else {
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51 type = 0;
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52 }
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53
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54 /* New prime generation makes the code even more cryptoish-insane. Do you know what this means!!!
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55 -- Gir: Yeah, oh wait, er, no.
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56 */
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57 if ((err = mp_prime_random_ex(N, mp_prime_rabin_miller_trials(len), len, type, rand_prime_helper, &rng)) != MP_OKAY) {
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58 return mpi_to_ltc_error(err);
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59 }
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60
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61 return CRYPT_OK;
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62 }
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63
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64 #endif
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65