+int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
+ {
+ return bnrand(0, rnd, bits, top, bottom);
+ }
+
+int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
+ {
+ return bnrand(1, rnd, bits, top, bottom);
+ }
+
+#if 1
+int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)
+ {
+ return bnrand(2, rnd, bits, top, bottom);
+ }
+#endif
+
+
+/* random number r: 0 <= r < range */
+static int bn_rand_range(int pseudo, BIGNUM *r, BIGNUM *range)
+ {
+ int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_rand;
+ int n;
+
+ if (range->neg || BN_is_zero(range))
+ {
+ BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
+ return 0;
+ }
+
+ n = BN_num_bits(range); /* n > 0 */
+
+ /* BN_is_bit_set(range, n - 1) always holds */
+
+ if (n == 1)
+ {
+ if (!BN_zero(r)) return 0;
+ }
+ else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3))
+ {
+ /* range = 100..._2,
+ * so 3*range (= 11..._2) is exactly one bit longer than range */
+ do
+ {
+ if (!bn_rand(r, n + 1, -1, 0)) return 0;
+ /* If r < 3*range, use r := r MOD range
+ * (which is either r, r - range, or r - 2*range).
+ * Otherwise, iterate once more.
+ * Since 3*range = 11..._2, each iteration succeeds with
+ * probability >= .75. */
+ if (BN_cmp(r ,range) >= 0)
+ {
+ if (!BN_sub(r, r, range)) return 0;
+ if (BN_cmp(r, range) >= 0)
+ if (!BN_sub(r, r, range)) return 0;
+ }
+ }
+ while (BN_cmp(r, range) >= 0);
+ }
+ else
+ {
+ do
+ {
+ /* range = 11..._2 or range = 101..._2 */
+ if (!bn_rand(r, n, -1, 0)) return 0;
+ }
+ while (BN_cmp(r, range) >= 0);
+ }
+
+ return 1;
+ }
+
+
+int BN_rand_range(BIGNUM *r, BIGNUM *range)
+ {
+ return bn_rand_range(0, r, range);
+ }
+
+int BN_pseudo_rand_range(BIGNUM *r, BIGNUM *range)
+ {
+ return bn_rand_range(1, r, range);
+ }