#define TABLE_SIZE 32
-int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
- BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)
+int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
+ const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
+ BN_CTX *ctx, BN_MONT_CTX *in_mont)
{
int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
int r_is_one=1,ts1=0,ts2=0;
BIGNUM *d,*r;
- BIGNUM *a_mod_m;
+ const BIGNUM *a_mod_m;
BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
BN_MONT_CTX *mont=NULL;
bits2=BN_num_bits(p2);
if ((bits1 == 0) && (bits2 == 0))
{
- BN_one(rr);
- return(1);
+ ret = BN_one(rr);
+ return ret;
}
+
bits=(bits1 > bits2)?bits1:bits2;
BN_CTX_start(ctx);
*/
BN_init(&val1[0]);
ts1=1;
- if (BN_ucmp(a1,m) >= 0)
+ if (a1->neg || BN_ucmp(a1,m) >= 0)
{
if (!BN_mod(&(val1[0]),a1,m,ctx))
goto err;
}
else
a_mod_m = a1;
+ if (BN_is_zero(a_mod_m))
+ {
+ ret = BN_zero(rr);
+ goto err;
+ }
+
if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err;
if (window1 > 1)
{
*/
BN_init(&val2[0]);
ts2=1;
- if (BN_ucmp(a2,m) >= 0)
+ if (a2->neg || BN_ucmp(a2,m) >= 0)
{
if (!BN_mod(&(val2[0]),a2,m,ctx))
goto err;
}
else
a_mod_m = a2;
+ if (BN_is_zero(a_mod_m))
+ {
+ ret = BN_zero(rr);
+ goto err;
+ }
if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err;
if (window2 > 1)
{
{
/* consider bits b-window1+1 .. b for this window */
i = b-window1+1;
- while (!BN_is_bit_set(p1, i))
+ while (!BN_is_bit_set(p1, i)) /* works for i<0 */
i++;
wpos1 = i;
wvalue1 = 1;