BIGNUM *BN_mod_inverse(BIGNUM *ret,BIGNUM *a, const BIGNUM *n,BN_CTX *ctx);
BIGNUM *BN_generate_prime(BIGNUM *ret,int bits,int safe,BIGNUM *add,
BIGNUM *rem,void (*callback)(int,int,void *),void *cb_arg);
-int BN_is_prime(BIGNUM *p,int nchecks,void (*callback)(int,int,void *),
+int BN_is_prime(const BIGNUM *p,int nchecks,
+ void (*callback)(int,int,void *),
BN_CTX *ctx,void *cb_arg);
-int BN_is_prime_fasttest(BIGNUM *p,int nchecks,
+int BN_is_prime_fasttest(const BIGNUM *p,int nchecks,
void (*callback)(int,int,void *),BN_CTX *ctx,void *cb_arg,
int do_trial_division);
void ERR_load_BN_strings(void );
return(found ? rnd : NULL);
}
-int BN_is_prime(BIGNUM *a, int checks, void (*callback)(int,int,void *),
+int BN_is_prime(const BIGNUM *a, int checks, void (*callback)(int,int,void *),
BN_CTX *ctx_passed, void *cb_arg)
{
return BN_is_prime_fasttest(a, checks, callback, ctx_passed, cb_arg, 0);
}
-int BN_is_prime_fasttest(BIGNUM *a, int checks,
+int BN_is_prime_fasttest(const BIGNUM *a, int checks,
void (*callback)(int,int,void *),
BN_CTX *ctx_passed, void *cb_arg,
int do_trial_division)
int i, j, ret = -1;
int k;
BN_CTX *ctx = NULL;
- BIGNUM *a1, *a1_odd, *check; /* taken from ctx */
+ BIGNUM *A1, *A1_odd, *check; /* taken from ctx */
BN_MONT_CTX *mont = NULL;
+ BIGNUM *A;
if (checks == BN_prime_checks)
checks = BN_prime_checks_for_size(BN_num_bits(a));
- if (a->neg) /* for now, refuse to handle negative numbers */
- return -1;
-
/* first look for small factors */
if (!BN_is_odd(a))
return(0);
else
if ((ctx=BN_CTX_new()) == NULL)
goto err;
- a1 = &(ctx->bn[ctx->tos++]);
- a1_odd = &(ctx->bn[ctx->tos++]);
+ /* A := abs(a) */
+ if (a->neg)
+ {
+ A = &(ctx->bn[ctx->tos++]);
+ BN_copy(A, a);
+ A->neg = 0;
+ }
+ else
+ A = a;
+ A1 = &(ctx->bn[ctx->tos++]);
+ A1_odd = &(ctx->bn[ctx->tos++]);
check = &(ctx->bn[ctx->tos++]);;
- /* 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))
+ if (!BN_sub_word(A1, 1))
goto err;
- if (BN_is_zero(a1))
+ if (BN_is_zero(A1))
{
ret = 0;
goto err;
}
- /* write a1 as a1_odd * 2^k */
+ /* write A1 as A1_odd * 2^k */
k = 1;
- while (!BN_is_bit_set(a1, k))
+ while (!BN_is_bit_set(A1, k))
k++;
- if (!BN_rshift(a1_odd, a1, k))
+ 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++)
{
- if (!BN_pseudo_rand(check, BN_num_bits(a1), 0, 0))
+ if (!BN_pseudo_rand(check, BN_num_bits(A1), 0, 0))
goto err;
- if (BN_cmp(check, a1) >= 0)
- if (!BN_sub(check, check, a1))
+ if (BN_cmp(check, A1) >= 0)
+ if (!BN_sub(check, check, A1))
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)
{
ret=1;
err:
if (ctx_passed != NULL)
- ctx_passed->tos -= 3; /* a1, a1_odd, check */
+ {
+ ctx_passed->tos -= 3; /* A1, A1_odd, check */
+ if (a != A)
+ --ctx_passed->tos; /* A */
+ }
else if (ctx != NULL)
BN_CTX_free(ctx);
if (mont != NULL)
BIGNUM *BN_generate_prime(BIGNUM *ret, int num, int safe, BIGNUM *add,
BIGNUM *rem, void (*callback)(int, int, void *), void *cb_arg);
- int BN_is_prime(BIGNUM *a, int checks, void (*callback)(int, int,
+ int BN_is_prime(const BIGNUM *a, int checks, void (*callback)(int, int,
void *), BN_CTX *ctx, void *cb_arg);
- int BN_is_prime_fasttest(BIGNUM *a, int checks, void (*callback)(int,
- int, void *), BN_CTX *ctx, void *cb_arg, int do_trial_division);
+ int BN_is_prime_fasttest(const BIGNUM *a, int checks,
+ void (*callback)(int, int, void *), BN_CTX *ctx, void *cb_arg,
+ int do_trial_division);
=head1 DESCRIPTION