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dsa_make_key: improved testing x < q

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Karel Miko 2013-10-10 00:53:04 +02:00 committed by Steffen Jaeckel
parent 24d03dd823
commit 72022edb8d
1 changed files with 5 additions and 4 deletions
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9
src/pk/dsa/dsa_make_key.c
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@ -29,7 +29,7 @@
int dsa_make_key(prng_state *prng, int wprng, int group_size, int modulus_size, dsa_key *key)
{
void *tmp, *tmp2;
int err, res;
int err, res, q_size;
unsigned char *buf;
LTC_ARGCHK(key != NULL);
@ -104,13 +104,14 @@ int dsa_make_key(prng_state *prng, int wprng, int group_size, int modulus_size,
/* 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
*/
q_size = mp_unsigned_bin_size(key->q);
do {
if (prng_descriptor[wprng].read(buf, group_size, prng) != (unsigned long)group_size) {
if (prng_descriptor[wprng].read(buf, q_size, prng) != (unsigned long)q_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_read_unsigned_bin(key->x, buf, q_size)) != CRYPT_OK) { goto error; }
} while (mp_cmp_d(key->x, 1) != LTC_MP_GT || mp_cmp(key->x, key->q) != LTC_MP_LT);
if ((err = mp_exptmod(key->g, key->x, key->p, key->y)) != CRYPT_OK) { goto error; }
key->type = PK_PRIVATE;