/**
Create an RSA key
@param size The size of the modulus (key size) desired (octets)
@param e The "e" value (public key). e==65537 is a good choice
@param key [out] Destination of a newly created private key pair
@return CRYPT_OK if successful, upon error all allocated ram is freed
*/
int rsa_make_key(int size, long e, rsa_key * key)
{
mp_int p, q, tmp1, tmp2, tmp3;
int err;
LTC_ARGCHK(key != NULL);
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)) != CRYPT_OK) {
return err;
}
/* make primes p and q (optimization provided by Wayne Scott) */
if ((err = mp_set_int(&tmp3, e)) != CRYPT_OK) {
goto cleanup;
}
/* tmp3 = e */
/* make prime "p" */
do {
if ((err = rand_prime(&p, size / 2)) != CRYPT_OK) {
goto cleanup;
}
if ((err = mp_sub_d(&p, 1, &tmp1)) != CRYPT_OK) {
goto cleanup;
} /* tmp1 = p-1 */
if ((err = mp_gcd(&tmp1, &tmp3, &tmp2)) != CRYPT_OK) {
goto cleanup;
} /* 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 / 2)) != CRYPT_OK) {
goto cleanup;
}
if ((err = mp_sub_d(&q, 1, &tmp1)) != CRYPT_OK) {
goto cleanup;
} /* tmp1 = q-1 */
if ((err = mp_gcd(&tmp1, &tmp3, &tmp2)) != CRYPT_OK) {
goto cleanup;
} /* 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)) != CRYPT_OK) {
goto cleanup;
}
/* tmp2 = p-1 */
/* tmp1 = q-1 (previous do/while loop) */
if ((err = mp_lcm(&tmp1, &tmp2, &tmp1)) != CRYPT_OK) {
goto cleanup;
}
/* 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)) != CRYPT_OK) {
goto cleanup;
}
if ((err = mp_set_int(&key->e, e)) != CRYPT_OK) {
goto errkey;
} /* key->e = e */
if ((err = mp_invmod(&key->e, &tmp1, &key->d)) != CRYPT_OK) {
goto errkey;
} /* key->d = 1/e mod lcm(p-1,q-1) */
if ((err = mp_mul(&p, &q, &key->N)) != CRYPT_OK) {
goto errkey;
}
/* 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)) != CRYPT_OK) {
goto errkey;
} /* tmp1 = q-1 */
if ((err = mp_sub_d(&q, 1, &tmp2)) != CRYPT_OK) {
goto errkey;
} /* tmp2 = p-1 */
if ((err = mp_mod(&key->d, &tmp1, &key->dP)) != CRYPT_OK) {
goto errkey;
} /* dP = d mod p-1 */
if ((err = mp_mod(&key->d, &tmp2, &key->dQ)) != CRYPT_OK) {
goto errkey;
} /* dQ = d mod q-1 */
if ((err = mp_invmod(&q, &p, &key->qP)) != CRYPT_OK) {
goto errkey;
}
/* qP = 1/q mod p */
if ((err = mp_copy(&p, &key->p)) != CRYPT_OK) {
goto errkey;
}
if ((err = mp_copy(&q, &key->q)) != CRYPT_OK) {
goto errkey;
}
/* set key type (in this case it's CRT optimized) */
key->type = PK_PRIVATE;
/* return ok and free temps */
err = CRYPT_OK;
goto cleanup;
errkey:
mp_clear_multi(&key->d, &key->e, &key->N, &key->dQ, &key->dP, &key->qP,
&key->p, &key->q, NULL);
cleanup:
mp_clear_multi(&tmp3, &tmp2, &tmp1, &p, &q, NULL);
return err;
}
/**
Create a DSA key
@param prng An active PRNG state
@param wprng The index of the PRNG desired
@param group_size Size of the multiplicative group (octets)
@param modulus_size Size of the modulus (octets)
@param key [out] Where to store the created key
@return CRYPT_OK if successful, upon error this function will free all allocated memory
*/
int dsa_make_key(prng_state *prng, int wprng, int group_size, int modulus_size, dsa_key *key)
{
void *tmp, *tmp2;
int err, res;
unsigned char *buf;
LTC_ARGCHK(key != NULL);
LTC_ARGCHK(ltc_mp.name != NULL);
/* check prng */
if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
return err;
}
/* check size */
if (group_size >= LTC_MDSA_MAX_GROUP || group_size <= 15 ||
group_size >= modulus_size || (modulus_size - group_size) >= LTC_MDSA_DELTA) {
return CRYPT_INVALID_ARG;
}
/* allocate ram */
buf = XMALLOC(LTC_MDSA_DELTA);
if (buf == NULL) {
return CRYPT_MEM;
}
/* init mp_ints */
if ((err = mp_init_multi(&tmp, &tmp2, &key->g, &key->q, &key->p, &key->x, &key->y, NULL)) != CRYPT_OK) {
XFREE(buf);
return err;
}
/* make our prime q */
if ((err = rand_prime(key->q, group_size, prng, wprng)) != CRYPT_OK) { goto error; }
/* double q */
if ((err = mp_add(key->q, key->q, tmp)) != CRYPT_OK) { goto error; }
/* now make a random string and multply it against q */
if (prng_descriptor[wprng]->read(buf+1, modulus_size - group_size, prng) != (unsigned long)(modulus_size - group_size)) {
err = CRYPT_ERROR_READPRNG;
goto error;
}
/* force magnitude */
buf[0] |= 0xC0;
/* force even */
buf[modulus_size - group_size - 1] &= ~1;
if ((err = mp_read_unsigned_bin(tmp2, buf, modulus_size - group_size)) != CRYPT_OK) { goto error; }
if ((err = mp_mul(key->q, tmp2, key->p)) != CRYPT_OK) { goto error; }
if ((err = mp_add_d(key->p, 1, key->p)) != CRYPT_OK) { goto error; }
/* now loop until p is prime */
for (;;) {
if ((err = mp_prime_is_prime(key->p, 8, &res)) != CRYPT_OK) { goto error; }
if (res == LTC_MP_YES) break;
/* add 2q to p and 2 to tmp2 */
if ((err = mp_add(tmp, key->p, key->p)) != CRYPT_OK) { goto error; }
if ((err = mp_add_d(tmp2, 2, tmp2)) != CRYPT_OK) { goto error; }
}
/* now p = (q * tmp2) + 1 is prime, find a value g for which g^tmp2 != 1 */
mp_set(key->g, 1);
do {
if ((err = mp_add_d(key->g, 1, key->g)) != CRYPT_OK) { goto error; }
if ((err = mp_exptmod(key->g, tmp2, key->p, tmp)) != CRYPT_OK) { goto error; }
} while (mp_cmp_d(tmp, 1) == LTC_MP_EQ);
/* at this point tmp generates a group of order q mod p */
mp_exch(tmp, key->g);
/* so now we have our DH structure, generator g, order q, modulus p
Now we need a random exponent [mod q] and it's power g^x mod p
*/
do {
if (prng_descriptor[wprng]->read(buf, group_size, prng) != (unsigned long)group_size) {
err = CRYPT_ERROR_READPRNG;
goto error;
}
if ((err = mp_read_unsigned_bin(key->x, buf, group_size)) != CRYPT_OK) { goto error; }
} while (mp_cmp_d(key->x, 1) != LTC_MP_GT);
if ((err = mp_exptmod(key->g, key->x, key->p, key->y)) != CRYPT_OK) { goto error; }
key->type = PK_PRIVATE;
key->qord = group_size;
#ifdef LTC_CLEAN_STACK
zeromem(buf, LTC_MDSA_DELTA);
#endif
err = CRYPT_OK;
goto done;
error:
mp_clear_multi(key->g, key->q, key->p, key->x, key->y, NULL);
done:
mp_clear_multi(tmp, tmp2, NULL);
XFREE(buf);
return err;
}
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;
}
int rsa_make_key(prng_state *prng, int wprng, int size, long e, rsa_key *key)
{
mp_int p, q, tmp1, tmp2, tmp3;
int res, err;
_ARGCHK(key != NULL);
if ((size < (1024/8)) || (size > (4096/8))) {
return CRYPT_INVALID_KEYSIZE;
}
if ((e < 3) || ((e & 1) == 0)) {
return CRYPT_INVALID_ARG;
}
if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
return err;
}
if (mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL) != MP_OKAY) {
return CRYPT_MEM;
}
/* make primes p and q (optimization provided by Wayne Scott) */
if (mp_set_int(&tmp3, e) != MP_OKAY) { goto error; } /* tmp3 = e */
/* make prime "p" */
do {
if (rand_prime(&p, size/2, prng, wprng) != CRYPT_OK) { res = CRYPT_ERROR; goto done; }
if (mp_sub_d(&p, 1, &tmp1) != MP_OKAY) { goto error; } /* tmp1 = p-1 */
if (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 (rand_prime(&q, size/2, prng, wprng) != CRYPT_OK) { res = CRYPT_ERROR; goto done; }
if (mp_sub_d(&q, 1, &tmp1) != MP_OKAY) { goto error; } /* tmp1 = q-1 */
if (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 (mp_sub_d(&p, 1, &tmp2) != MP_OKAY) { goto error; } /* tmp2 = p-1 */
/* tmp1 = q-1 (previous do/while loop) */
if (mp_lcm(&tmp1, &tmp2, &tmp1) != MP_OKAY) { goto error; } /* tmp1 = lcm(p-1, q-1) */
/* make key */
if (mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP,
&key->qP, &key->pQ, &key->p, &key->q, NULL) != MP_OKAY) {
goto error;
}
if (mp_set_int(&key->e, e) != MP_OKAY) { goto error2; } /* key->e = e */
if (mp_invmod(&key->e, &tmp1, &key->d) != MP_OKAY) { goto error2; } /* key->d = 1/e mod lcm(p-1,q-1) */
if (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 (mp_sub_d(&p, 1, &tmp1) != MP_OKAY) { goto error2; } /* tmp1 = q-1 */
if (mp_sub_d(&q, 1, &tmp2) != MP_OKAY) { goto error2; } /* tmp2 = p-1 */
if (mp_mod(&key->d, &tmp1, &key->dP) != MP_OKAY) { goto error2; } /* dP = d mod p-1 */
if (mp_mod(&key->d, &tmp2, &key->dQ) != MP_OKAY) { goto error2; } /* dQ = d mod q-1 */
if (mp_invmod(&q, &p, &key->qP) != MP_OKAY) { goto error2; } /* qP = 1/q mod p */
if (mp_mulmod(&key->qP, &q, &key->N, &key->qP)) { goto error2; } /* qP = q * (1/q mod p) mod N */
if (mp_invmod(&p, &q, &key->pQ) != MP_OKAY) { goto error2; } /* pQ = 1/p mod q */
if (mp_mulmod(&key->pQ, &p, &key->N, &key->pQ)) { goto error2; } /* pQ = p * (1/p mod q) mod N */
if (mp_copy(&p, &key->p) != MP_OKAY) { goto error2; }
if (mp_copy(&q, &key->q) != MP_OKAY) { goto error2; }
/* shrink ram required */
if (mp_shrink(&key->e) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->d) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->N) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->dQ) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->dP) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->qP) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->pQ) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->p) != MP_OKAY) { goto error2; }
if (mp_shrink(&key->q) != MP_OKAY) { goto error2; }
res = CRYPT_OK;
key->type = PK_PRIVATE_OPTIMIZED;
goto done;
error2:
mp_clear_multi(&key->d, &key->e, &key->N, &key->dQ, &key->dP,
&key->qP, &key->pQ, &key->p, &key->q, NULL);
error:
res = CRYPT_MEM;
done:
mp_clear_multi(&tmp3, &tmp2, &tmp1, &p, &q, NULL);
return res;
}
/* Make an RSA key for size bits, with e specified, 65537 is a good e */
int MakeRsaKey(RsaKey* key, int size, long e, RNG* rng)
{
mp_int p, q, tmp1, tmp2, tmp3;
int err;
if (key == NULL || rng == NULL)
return BAD_FUNC_ARG;
if (size < RSA_MIN_SIZE || size > RSA_MAX_SIZE)
return BAD_FUNC_ARG;
if (e < 3 || (e & 1) == 0)
return BAD_FUNC_ARG;
if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL)) != MP_OKAY)
return err;
err = mp_set_int(&tmp3, e);
/* make p */
if (err == MP_OKAY) {
do {
err = rand_prime(&p, size/16, rng, key->heap); /* size in bytes/2 */
if (err == MP_OKAY)
err = mp_sub_d(&p, 1, &tmp1); /* tmp1 = p-1 */
if (err == MP_OKAY)
err = mp_gcd(&tmp1, &tmp3, &tmp2); /* tmp2 = gcd(p-1, e) */
} while (err == MP_OKAY && mp_cmp_d(&tmp2, 1) != 0); /* e divdes p-1 */
}
/* make q */
if (err == MP_OKAY) {
do {
err = rand_prime(&q, size/16, rng, key->heap); /* size in bytes/2 */
if (err == MP_OKAY)
err = mp_sub_d(&q, 1, &tmp1); /* tmp1 = q-1 */
if (err == MP_OKAY)
err = mp_gcd(&tmp1, &tmp3, &tmp2); /* tmp2 = gcd(q-1, e) */
} while (err == MP_OKAY && mp_cmp_d(&tmp2, 1) != 0); /* e divdes q-1 */
}
if (err == MP_OKAY)
err = mp_init_multi(&key->n, &key->e, &key->d, &key->p, &key->q, NULL);
if (err == MP_OKAY)
err = mp_init_multi(&key->dP, &key->dQ, &key->u, NULL, NULL, NULL);
if (err == MP_OKAY)
err = mp_sub_d(&p, 1, &tmp2); /* tmp2 = p-1 */
if (err == MP_OKAY)
err = mp_lcm(&tmp1, &tmp2, &tmp1); /* tmp1 = lcm(p-1, q-1),last loop */
/* make key */
if (err == MP_OKAY)
err = mp_set_int(&key->e, e); /* key->e = e */
if (err == MP_OKAY) /* key->d = 1/e mod lcm(p-1, q-1) */
err = mp_invmod(&key->e, &tmp1, &key->d);
if (err == MP_OKAY)
err = mp_mul(&p, &q, &key->n); /* key->n = pq */
if (err == MP_OKAY)
err = mp_sub_d(&p, 1, &tmp1);
if (err == MP_OKAY)
err = mp_sub_d(&q, 1, &tmp2);
if (err == MP_OKAY)
err = mp_mod(&key->d, &tmp1, &key->dP);
if (err == MP_OKAY)
err = mp_mod(&key->d, &tmp2, &key->dQ);
if (err == MP_OKAY)
err = mp_invmod(&q, &p, &key->u);
if (err == MP_OKAY)
err = mp_copy(&p, &key->p);
if (err == MP_OKAY)
err = mp_copy(&q, &key->q);
if (err == MP_OKAY)
key->type = RSA_PRIVATE;
mp_clear(&tmp3);
mp_clear(&tmp2);
mp_clear(&tmp1);
mp_clear(&q);
mp_clear(&p);
if (err != MP_OKAY) {
FreeRsaKey(key);
return err;
}
return 0;
}
