Numbers greater than 1 are usually non-negative.
BN_is_prime_fasttest_ex begins by rejecting if a <= 1. Then it goes to
set A := abs(a), but a cannot be negative at this point.
@@ -158,7 +158,6 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
BN_CTX *ctx = NULL;
BIGNUM *A1, *A1_odd, *check; /* taken from ctx */
BN_MONT_CTX *mont = NULL;
- const BIGNUM *A = NULL;
if (BN_cmp(a, BN_value_one()) <= 0)
return 0;
@@ -188,25 +187,14 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
goto err;
BN_CTX_start(ctx);
- /* A := abs(a) */
- if (a->neg) {
- BIGNUM *t;
- if ((t = BN_CTX_get(ctx)) == NULL)
- goto err;
- if (BN_copy(t, a) == NULL)
- goto err;
- t->neg = 0;
- A = t;
- } else
- A = a;
A1 = BN_CTX_get(ctx);
A1_odd = BN_CTX_get(ctx);
check = BN_CTX_get(ctx);
if (check == NULL)
goto err;
- /* compute A1 := A - 1 */
- if (!BN_copy(A1, A))
+ /* compute A1 := a - 1 */
+ if (!BN_copy(A1, a))
goto err;
if (!BN_sub_word(A1, 1))
goto err;
@@ -222,11 +210,11 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
if (!BN_rshift(A1_odd, A1, k))
goto err;
- /* Montgomery setup for computations mod A */
+ /* Montgomery setup for computations mod a */
mont = BN_MONT_CTX_new();
if (mont == NULL)
goto err;
- if (!BN_MONT_CTX_set(mont, A, ctx))
+ if (!BN_MONT_CTX_set(mont, a, ctx))
goto err;
for (i = 0; i < checks; i++) {
@@ -234,9 +222,9 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
goto err;
if (!BN_add_word(check, 1))
goto err;
- /* now 1 <= check < A */
+ /* now 1 <= check < a */
- j = witness(check, A, A1, A1_odd, k, ctx, mont);
+ j = witness(check, a, A1, A1_odd, k, ctx, mont);
if (j == -1)
goto err;
if (j) {
