#define BN_mask_word(x, m) ((x->d[0]) & (m))
BN_MONTGOMERY *BN_mont_new()
-{
+ {
BN_MONTGOMERY *ret;
ret=(BN_MONTGOMERY *)malloc(sizeof(BN_MONTGOMERY));
if (ret == NULL) return NULL;
if ((ret->p = BN_new()) == NULL)
- {
+ {
free(ret);
return NULL;
- }
+ }
return ret;
-}
+ }
void BN_mont_clear_free(BN_MONTGOMERY *mont)
-{
+ {
if (mont == NULL) return;
if (mont->p != NULL) BN_clear_free(mont->p);
mont->p_num_bytes = 0;
mont->R_num_bits = 0;
mont->p_inv_b_neg = 0;
-}
+ }
+
int BN_to_mont(BIGNUM *x, BN_MONTGOMERY *mont, BN_CTX *ctx)
-{
+ {
assert(x != NULL);
assert(mont != NULL);
if (!BN_mod(x, x, mont->p, ctx)) return 0;
return 1;
-}
+ }
static BN_ULONG BN_mont_inv(BIGNUM *a, int e, BN_CTX *ctx)
/* y = a^{-1} (mod 2^e) for an odd number a */
-{
+ {
BN_ULONG y, exp, mask;
BIGNUM *x, *xy, *x_sh;
int i;
if((x = BN_dup(a)) == NULL) return 0;
if(!BN_mask_bits(x, e)) return 0;
- xy = ctx->bn[ctx->tos];
- x_sh = ctx->bn[ctx->tos + 1];
- ctx->tos += 2;
+ BN_CTX_start(ctx);
+ xy = BN_CTX_get(ctx);
+ x_sh = BN_CTX_get(ctx);
+ if (x_sh == NULL) goto err;
if (BN_copy(xy, x) == NULL) goto err;
if (!BN_lshift1(x_sh, x)) goto err;
for (i = 2; i <= e; i++)
- {
- if (exp < BN_mask_word(xy, mask))
{
+ if (exp < BN_mask_word(xy, mask))
+ {
y = y + exp;
if (!BN_add(xy, xy, x_sh)) goto err;
- }
+ }
exp <<= 1;
if (!BN_lshift1(x_sh, x_sh)) goto err;
mask <<= 1;
mask++;
- }
+ }
#ifdef TEST
#endif
if (x != NULL) BN_clear_free(x);
- ctx->tos -= 2;
+ BN_CTX_end(ctx);
return y;
err:
if (x != NULL) BN_clear_free(x);
- ctx->tos -= 2;
+ BN_CTX_end(ctx);
return 0;
+ }
-}
int BN_mont_set(BIGNUM *p, BN_MONTGOMERY *mont, BN_CTX *ctx)
-{
+ {
assert(p != NULL && ctx != NULL);
assert(mont != NULL);
assert(mont->p != NULL);
mont->p_inv_b_neg = 0 - mont->p_inv_b_neg;
return 1;
-}
+ }
+
static int BN_cpy_mul_word(BIGNUM *ret, BIGNUM *a, BN_ULONG w)
/* ret = a * w */
-{
+ {
if (BN_copy(ret, a) == NULL) return 0;
if (!BN_mul_word(ret, w)) return 0;
return 1;
-}
+ }
int BN_mont_red(BIGNUM *y, BN_MONTGOMERY *mont, BN_CTX *ctx)
/* yR^{-1} (mod p) */
-{
+ {
int i;
BIGNUM *up, *p;
BN_ULONG u;
if (BN_is_zero(y)) return 1;
p = mont->p;
- up = ctx->bn[ctx->tos];
- ctx->tos += 1;
+ BN_CTX_start(ctx);
+ up = BN_CTX_get(ctx);
+ if (up == NULL) goto err;
for (i = 0; i < mont->p_num_bytes; i++)
- {
+ {
u = (y->d[0]) * mont->p_inv_b_neg; /* u = y_0 * p' */
if (!BN_cpy_mul_word(up, p, u)) goto err; /* up = u * p */
if (y->d[0]) goto err;
#endif
if (!BN_rshift(y, y, BN_BITS2)) goto err; /* y = (y + up)/b */
- }
+ }
- if (BN_cmp(y, mont->p) >= 0)
- {
+ if (BN_cmp(y, mont->p) >= 0)
+ {
if (!BN_sub(y, y, mont->p)) goto err;
- }
+ }
- ctx->tos -= 1;
+ BN_CTX_end(ctx);
return 1;
err:
- ctx->tos -= 1;
+ BN_CTX_end(ctx);
return 0;
-
-}
+ }
int BN_mont_mod_mul(BIGNUM *r, BIGNUM *x, BIGNUM *y, BN_MONTGOMERY *mont, BN_CTX *ctx)
/* r = x * y mod p */
/* r != x && r! = y !!! */
-{
+ {
BIGNUM *xiy, *up;
BN_ULONG u;
int i;
assert(!y->neg);
if (BN_is_zero(x) || BN_is_zero(y))
- {
+ {
if (!BN_zero(r)) return 0;
return 1;
- }
+ }
- xiy = ctx->bn[ctx->tos];
- up = ctx->bn[ctx->tos + 1];
- ctx->tos += 2;
+ BN_CTX_start(ctx);
+ xiy = BN_CTX_get(ctx);
+ up = BN_CTX_get(ctx);
+ if (up == NULL) goto err;
if (!BN_zero(r)) goto err;
for (i = 0; i < x->top; i++)
- {
+ {
u = (r->d[0] + x->d[i] * y->d[0]) * mont->p_inv_b_neg;
if (!BN_cpy_mul_word(xiy, y, x->d[i])) goto err;
#ifdef TEST
if (r->d[0]) goto err;
#endif
- if (!BN_rshift(r, r, BN_BITS2)) goto err;
- }
+ if (!BN_rshift(r, r, BN_BITS2)) goto err;
+ }
for (i = x->top; i < mont->p_num_bytes; i++)
- {
+ {
u = (r->d[0]) * mont->p_inv_b_neg;
if (!BN_cpy_mul_word(up, mont->p, u)) goto err;
#ifdef TEST
if (r->d[0]) goto err;
#endif
- if (!BN_rshift(r, r, BN_BITS2)) goto err;
- }
+ if (!BN_rshift(r, r, BN_BITS2)) goto err;
+ }
- if (BN_cmp(r, mont->p) >= 0)
- {
+ if (BN_cmp(r, mont->p) >= 0)
+ {
if (!BN_sub(r, r, mont->p)) goto err;
- }
+ }
- ctx->tos -= 2;
+ BN_CTX_end(ctx);
return 1;
err:
- ctx->tos -= 2;
+ BN_CTX_end(ctx);
return 0;
-}
+ }