1 /* crypto/bn/bn_rand.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
58 /* ====================================================================
59 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved.
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
87 * 6. Redistributions of any form whatsoever must retain the following
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
114 #include "cryptlib.h"
116 #include <openssl/rand.h>
118 static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
120 unsigned char *buf = NULL;
121 int ret = 0, bit, bytes, mask;
129 bytes = (bits + 7) / 8;
130 bit = (bits - 1) % 8;
131 mask = 0xff << (bit + 1);
133 buf = (unsigned char *)OPENSSL_malloc(bytes);
135 BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE);
139 /* make a random number and set the top and bottom bits */
141 RAND_add(&tim, sizeof(tim), 0.0);
144 if (RAND_pseudo_bytes(buf, bytes) == -1)
147 if (RAND_bytes(buf, bytes) <= 0)
152 if (pseudorand == 2) {
154 * generate patterns that are more likely to trigger BN library bugs
159 for (i = 0; i < bytes; i++) {
160 RAND_pseudo_bytes(&c, 1);
161 if (c >= 128 && i > 0)
177 buf[0] |= (3 << (bit - 1));
180 buf[0] |= (1 << bit);
184 if (bottom) /* set bottom bit if requested */
186 if (!BN_bin2bn(buf, bytes, rnd))
191 OPENSSL_cleanse(buf, bytes);
198 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
200 return bnrand(0, rnd, bits, top, bottom);
203 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
205 return bnrand(1, rnd, bits, top, bottom);
209 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)
211 return bnrand(2, rnd, bits, top, bottom);
215 /* random number r: 0 <= r < range */
216 static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range)
218 int (*bn_rand) (BIGNUM *, int, int, int) =
219 pseudo ? BN_pseudo_rand : BN_rand;
223 if (range->neg || BN_is_zero(range)) {
224 BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
228 n = BN_num_bits(range); /* n > 0 */
230 /* BN_is_bit_set(range, n - 1) always holds */
234 else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) {
236 * range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer
240 if (!bn_rand(r, n + 1, -1, 0))
243 * If r < 3*range, use r := r MOD range (which is either r, r -
244 * range, or r - 2*range). Otherwise, iterate once more. Since
245 * 3*range = 11..._2, each iteration succeeds with probability >=
248 if (BN_cmp(r, range) >= 0) {
249 if (!BN_sub(r, r, range))
251 if (BN_cmp(r, range) >= 0)
252 if (!BN_sub(r, r, range))
257 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
262 while (BN_cmp(r, range) >= 0);
265 /* range = 11..._2 or range = 101..._2 */
266 if (!bn_rand(r, n, -1, 0))
270 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
274 while (BN_cmp(r, range) >= 0);
281 int BN_rand_range(BIGNUM *r, const BIGNUM *range)
283 return bn_rand_range(0, r, range);
286 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range)
288 return bn_rand_range(1, r, range);