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Sweden-Number/dlls/rsaenh/rsa.c

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/*
* dlls/rsaenh/rsa.c
* RSA public key cryptographic functions
*
* Copyright 2004 Michael Jung
* Based on public domain code by Tom St Denis (tomstdenis@iahu.ca)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* This file contains code from the LibTomCrypt cryptographic
* library written by Tom St Denis (tomstdenis@iahu.ca). LibTomCrypt
* is in the public domain. The code in this file is tailored to
* special requirements. Take a look at http://libtomcrypt.org for the
* original version.
*/
#include "tomcrypt.h"
static const struct {
int mpi_code, ltc_code;
} mpi_to_ltc_codes[] = {
{ MP_OKAY , CRYPT_OK},
{ MP_MEM , CRYPT_MEM},
{ MP_VAL , CRYPT_INVALID_ARG},
};
/* convert a MPI error to a LTC error (Possibly the most powerful function ever! Oh wait... no) */
int mpi_to_ltc_error(int err)
{
int x;
for (x = 0; x < (int)(sizeof(mpi_to_ltc_codes)/sizeof(mpi_to_ltc_codes[0])); x++) {
if (err == mpi_to_ltc_codes[x].mpi_code) {
return mpi_to_ltc_codes[x].ltc_code;
}
}
return CRYPT_ERROR;
}
extern int gen_rand_impl(unsigned char *dst, unsigned int len);
static int rand_prime_helper(unsigned char *dst, int len, void *dat)
{
return gen_rand_impl(dst, len) ? len : 0;
}
int rand_prime(mp_int *N, long len)
{
int type;
/* allow sizes between 2 and 256 bytes for a prime size */
if (len < 16 || len > 8192) {
printf("Invalid prime size!\n");
return CRYPT_INVALID_PRIME_SIZE;
}
/* get type */
if (len < 0) {
type = LTM_PRIME_BBS;
len = -len;
} else {
type = 0;
}
/* 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, NULL));
}
int rsa_make_key(int size, long e, rsa_key *key)
{
mp_int p, q, tmp1, tmp2, tmp3;
int err;
if ((size < (MIN_RSA_SIZE/8)) || (size > (MAX_RSA_SIZE/8))) {
return CRYPT_INVALID_KEYSIZE;
}
if ((e < 3) || ((e & 1) == 0)) {
return CRYPT_INVALID_ARG;
}
if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL)) != MP_OKAY) {
return mpi_to_ltc_error(err);
}
/* make primes p and q (optimization provided by Wayne Scott) */
if ((err = mp_set_int(&tmp3, e)) != MP_OKAY) { goto error; } /* tmp3 = e */
/* make prime "p" */
do {
if ((err = rand_prime(&p, size*4)) != CRYPT_OK) { goto done; }
if ((err = mp_sub_d(&p, 1, &tmp1)) != MP_OKAY) { goto error; } /* tmp1 = p-1 */
if ((err = mp_gcd(&tmp1, &tmp3, &tmp2)) != MP_OKAY) { goto error; } /* tmp2 = gcd(p-1, e) */
} while (mp_cmp_d(&tmp2, 1) != 0); /* while e divides p-1 */
/* make prime "q" */
do {
if ((err = rand_prime(&q, size*4)) != CRYPT_OK) { goto done; }
if ((err = mp_sub_d(&q, 1, &tmp1)) != MP_OKAY) { goto error; } /* tmp1 = q-1 */
if ((err = mp_gcd(&tmp1, &tmp3, &tmp2)) != MP_OKAY) { goto error; } /* tmp2 = gcd(q-1, e) */
} while (mp_cmp_d(&tmp2, 1) != 0); /* while e divides q-1 */
/* tmp1 = lcm(p-1, q-1) */
if ((err = mp_sub_d(&p, 1, &tmp2)) != MP_OKAY) { goto error; } /* tmp2 = p-1 */
/* tmp1 = q-1 (previous do/while loop) */
if ((err = mp_lcm(&tmp1, &tmp2, &tmp1)) != MP_OKAY) { goto error; } /* tmp1 = lcm(p-1, q-1) */
/* make key */
if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP,
&key->qP, &key->p, &key->q, NULL)) != MP_OKAY) {
goto error;
}
if ((err = mp_set_int(&key->e, e)) != MP_OKAY) { goto error2; } /* key->e = e */
if ((err = mp_invmod(&key->e, &tmp1, &key->d)) != MP_OKAY) { goto error2; } /* key->d = 1/e mod lcm(p-1,q-1) */
if ((err = mp_mul(&p, &q, &key->N)) != MP_OKAY) { goto error2; } /* key->N = pq */
/* optimize for CRT now */
/* find d mod q-1 and d mod p-1 */
if ((err = mp_sub_d(&p, 1, &tmp1)) != MP_OKAY) { goto error2; } /* tmp1 = q-1 */
if ((err = mp_sub_d(&q, 1, &tmp2)) != MP_OKAY) { goto error2; } /* tmp2 = p-1 */
if ((err = mp_mod(&key->d, &tmp1, &key->dP)) != MP_OKAY) { goto error2; } /* dP = d mod p-1 */
if ((err = mp_mod(&key->d, &tmp2, &key->dQ)) != MP_OKAY) { goto error2; } /* dQ = d mod q-1 */
if ((err = mp_invmod(&q, &p, &key->qP)) != MP_OKAY) { goto error2; } /* qP = 1/q mod p */
if ((err = mp_copy(&p, &key->p)) != MP_OKAY) { goto error2; }
if ((err = mp_copy(&q, &key->q)) != MP_OKAY) { goto error2; }
/* shrink ram required */
if ((err = mp_shrink(&key->e)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->d)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->N)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->dQ)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->dP)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->qP)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->p)) != MP_OKAY) { goto error2; }
if ((err = mp_shrink(&key->q)) != MP_OKAY) { goto error2; }
/* 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->e, &key->N, &key->dQ, &key->dP,
&key->qP, &key->p, &key->q, NULL);
error:
err = mpi_to_ltc_error(err);
done:
mp_clear_multi(&tmp3, &tmp2, &tmp1, &p, &q, NULL);
return err;
}
void rsa_free(rsa_key *key)
{
mp_clear_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP,
&key->qP, &key->p, &key->q, NULL);
}
/* compute an RSA modular exponentiation */
int rsa_exptmod(const unsigned char *in, unsigned long inlen,
unsigned char *out, unsigned long *outlen, int which,
rsa_key *key)
{
mp_int tmp, tmpa, tmpb;
unsigned long x;
int err;
/* is the key of the right type for the operation? */
if (which == PK_PRIVATE && (key->type != PK_PRIVATE)) {
return CRYPT_PK_NOT_PRIVATE;
}
/* must be a private or public operation */
if (which != PK_PRIVATE && which != PK_PUBLIC) {
return CRYPT_PK_INVALID_TYPE;
}
/* init and copy into tmp */
if ((err = mp_init_multi(&tmp, &tmpa, &tmpb, NULL)) != MP_OKAY) { return mpi_to_ltc_error(err); }
if ((err = mp_read_unsigned_bin(&tmp, (unsigned char *)in, (int)inlen)) != MP_OKAY) { goto error; }
/* sanity check on the input */
if (mp_cmp(&key->N, &tmp) == MP_LT) {
err = CRYPT_PK_INVALID_SIZE;
goto done;
}
/* are we using the private exponent and is the key optimized? */
if (which == PK_PRIVATE) {
/* tmpa = tmp^dP mod p */
if ((err = mpi_to_ltc_error(mp_exptmod(&tmp, &key->dP, &key->p, &tmpa))) != MP_OKAY) { goto error; }
/* tmpb = tmp^dQ mod q */
if ((err = mpi_to_ltc_error(mp_exptmod(&tmp, &key->dQ, &key->q, &tmpb))) != MP_OKAY) { goto error; }
/* tmp = (tmpa - tmpb) * qInv (mod p) */
if ((err = mp_sub(&tmpa, &tmpb, &tmp)) != MP_OKAY) { goto error; }
if ((err = mp_mulmod(&tmp, &key->qP, &key->p, &tmp)) != MP_OKAY) { goto error; }
/* tmp = tmpb + q * tmp */
if ((err = mp_mul(&tmp, &key->q, &tmp)) != MP_OKAY) { goto error; }
if ((err = mp_add(&tmp, &tmpb, &tmp)) != MP_OKAY) { goto error; }
} else {
/* exptmod it */
if ((err = mp_exptmod(&tmp, &key->e, &key->N, &tmp)) != MP_OKAY) { goto error; }
}
/* read it back */
x = (unsigned long)mp_unsigned_bin_size(&key->N);
if (x > *outlen) {
err = CRYPT_BUFFER_OVERFLOW;
goto done;
}
*outlen = x;
/* convert it */
memset(out, 0, x);
if ((err = mp_to_unsigned_bin(&tmp, out+(x-mp_unsigned_bin_size(&tmp)))) != MP_OKAY) { goto error; }
/* clean up and return */
err = CRYPT_OK;
goto done;
error:
err = mpi_to_ltc_error(err);
done:
mp_clear_multi(&tmp, &tmpa, &tmpb, NULL);
return err;
}
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