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Prime Number Testing

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1. Update the function wolfSSL_BN_is_prime_ex to use mp_prime_is_prime_ex.
2. Modified fast and normal mp_prime_is_prime_ex() to use random numbers
that are in the range 2 < a < n-2.
This commit is contained in:
John Safranek
2018-07-10 14:24:05 -07:00
parent f1c3098bdc
commit 0e06f6413d
3 changed files with 99 additions and 15 deletions
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31
wolfcrypt/src/integer.c
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@@ -4609,9 +4609,10 @@ LBL_B:mp_clear (&b);
*/
int mp_prime_is_prime_ex (mp_int * a, int t, int *result, WC_RNG *rng)
{
mp_int b;
mp_int b, c;
int ix, err, res;
byte scratch[16];
byte* base = NULL;
word32 baseSz = 0;
/* default to no */
*result = MP_NO;
@@ -4643,19 +4644,39 @@ int mp_prime_is_prime_ex (mp_int * a, int t, int *result, WC_RNG *rng)
if ((err = mp_init (&b)) != MP_OKAY) {
return err;
}
if ((err = mp_init (&c)) != MP_OKAY) {
mp_clear(&b);
return err;
}
baseSz = mp_count_bits(a);
baseSz = (baseSz / 8) + (baseSz % 8) ? 1 : 0;
base = (byte*)XMALLOC(baseSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (base == NULL) {
err = MP_MEM;
goto LBL_B;
}
if ((err = mp_copy(a, 2, &c)) != MP_OKAY) {
goto LBL_B;
}
/* now do a miller rabin with up to t random numbers, this should
* give a (1/4)^t chance of a false prime. */
for (ix = 0; ix < t; ix++) {
/* Set a test candidate. */
if ((err = wc_RNG_GenerateBlock(rng, scratch, sizeof(scratch))) != 0) {
if ((err = wc_RNG_GenerateBlock(rng, base, baseSz)) != 0) {
goto LBL_B;
}
if ((err = mp_read_unsigned_bin(&b, scratch, sizeof(scratch))) != MP_OKAY) {
if ((err = mp_read_unsigned_bin(&b, base, baseSz)) != MP_OKAY) {
goto LBL_B;
}
if (mp_cmp_d(&b, 2) != MP_GT || mp_cmp(&b, &c) != MP_LT)
continue;
if ((err = mp_prime_miller_rabin (a, &b, &res)) != MP_OKAY) {
goto LBL_B;
}
@@ -4668,6 +4689,8 @@ int mp_prime_is_prime_ex (mp_int * a, int t, int *result, WC_RNG *rng)
/* passed the test */
*result = MP_YES;
LBL_B:mp_clear (&b);
mp_clear (&c);
XFREE(base, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return err;
}