bugfix in final fips loop II: alternative version
diff --git a/bn_mp_prime_is_prime.c b/bn_mp_prime_is_prime.c
index 5efab41..b9cb396 100644
--- a/bn_mp_prime_is_prime.c
+++ b/bn_mp_prime_is_prime.c
@@ -332,11 +332,11 @@ int mp_prime_is_prime(const mp_int *a, int t, int *result)
}
/*
* That number might got too big and the witness has to be
- * smaller than or equal to "a"
+ * smaller than "a"
*/
len = mp_count_bits(&b);
- if (len > size_a) {
- len = len - size_a;
+ if (len >= size_a) {
+ len = (len - size_a) + 1;
if ((err = mp_div_2d(&b, len, &b, NULL)) != MP_OKAY) {
goto LBL_B;
}
@@ -346,11 +346,6 @@ int mp_prime_is_prime(const mp_int *a, int t, int *result)
ix--;
continue;
}
- /* Witness and test subject must not be equal */
- if ( (size_a == mp_count_bits(&b)) && (mp_cmp(a, &b) == MP_EQ) ) {
- ix--;
- continue;
- }
if ((err = mp_prime_miller_rabin(a, &b, &res)) != MP_OKAY) {
goto LBL_B;
}