diff options
Diffstat (limited to 'src/pk/katja/katja_make_key.c')
| -rw-r--r-- | src/pk/katja/katja_make_key.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/pk/katja/katja_make_key.c b/src/pk/katja/katja_make_key.c new file mode 100644 index 0000000..08016c8 --- /dev/null +++ b/src/pk/katja/katja_make_key.c @@ -0,0 +1,101 @@ +/* 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.com + */ +#include "tomcrypt.h" + +/** + @file katja_make_key.c + Katja key generation, Tom St Denis +*/ + +#ifdef MKAT + +/** + Create a Katja key + @param prng An active PRNG state + @param wprng The index of the PRNG desired + @param size The size of the modulus (key size) desired (octets) + @param key [out] Destination of a newly created private key pair + @return CRYPT_OK if successful, upon error all allocated ram is freed +*/ +int katja_make_key(prng_state *prng, int wprng, int size, katja_key *key) +{ + void *p, *q, *tmp1, *tmp2; + int err; + + LTC_ARGCHK(key != NULL); + LTC_ARGCHK(ltc_mp.name != NULL); + + if ((size < (MIN_KAT_SIZE/8)) || (size > (MAX_KAT_SIZE/8))) { + return CRYPT_INVALID_KEYSIZE; + } + + if ((err = prng_is_valid(wprng)) != CRYPT_OK) { + return err; + } + + if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, NULL)) != CRYPT_OK) { + return err; + } + + /* divide size by three */ + size = (((size << 3) / 3) + 7) >> 3; + + /* make prime "q" (we negate size to make q == 3 mod 4) */ + if ((err = rand_prime(q, -size, prng, wprng)) != CRYPT_OK) { goto done; } + if ((err = mp_sub_d(q, 1, tmp1)) != CRYPT_OK) { goto done; } + + /* make prime "p" */ + do { + if ((err = rand_prime(p, size+1, prng, wprng)) != CRYPT_OK) { goto done; } + if ((err = mp_gcd(p, tmp1, tmp2)) != CRYPT_OK) { goto done; } + } while (mp_cmp_d(tmp2, 1) != LTC_MP_EQ); + + /* make key */ + if ((err = mp_init_multi(&key->d, &key->N, &key->dQ, &key->dP, + &key->qP, &key->p, &key->q, &key->pq, NULL)) != CRYPT_OK) { + goto error; + } + + /* n=p^2q and 1/n mod pq */ + if ((err = mp_copy( p, key->p)) != CRYPT_OK) { goto error2; } + if ((err = mp_copy( q, key->q)) != CRYPT_OK) { goto error2; } + if ((err = mp_mul(key->p, key->q, key->pq)) != CRYPT_OK) { goto error2; } /* tmp1 = pq */ + if ((err = mp_mul(key->pq, key->p, key->N)) != CRYPT_OK) { goto error2; } /* N = p^2q */ + if ((err = mp_sub_d( p, 1, tmp1)) != CRYPT_OK) { goto error2; } /* tmp1 = q-1 */ + if ((err = mp_sub_d( q, 1, tmp2)) != CRYPT_OK) { goto error2; } /* tmp2 = p-1 */ + if ((err = mp_lcm(tmp1, tmp2, key->d)) != CRYPT_OK) { goto error2; } /* tmp1 = lcd(p-1,q-1) */ + if ((err = mp_invmod( key->N, key->d, key->d)) != CRYPT_OK) { goto error2; } /* key->d = 1/N mod pq */ + + /* optimize for CRT now */ + /* find d mod q-1 and d mod p-1 */ + if ((err = mp_mod( key->d, tmp1, key->dP)) != CRYPT_OK) { goto error2; } /* dP = d mod p-1 */ + if ((err = mp_mod( key->d, tmp2, key->dQ)) != CRYPT_OK) { goto error2; } /* dQ = d mod q-1 */ + if ((err = mp_invmod( q, p, key->qP)) != CRYPT_OK) { goto error2; } /* qP = 1/q mod p */ + + /* set key type (in this case it's CRT optimized) */ + key->type = PK_PRIVATE; + + /* return ok and free temps */ + err = CRYPT_OK; + goto done; +error2: + mp_clear_multi( key->d, key->N, key->dQ, key->dP, key->qP, key->p, key->q, key->pq, NULL); +error: +done: + mp_clear_multi( tmp2, tmp1, p, q, NULL); + return err; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/katja/katja_make_key.c,v $ */ +/* $Revision: 1.10 $ */ +/* $Date: 2006/03/31 14:15:35 $ */ |