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).
112 #define OPENSSL_FIPSAPI
116 #include "cryptlib.h"
118 #include <openssl/rand.h>
119 #include <openssl/sha.h>
121 static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
123 unsigned char *buf=NULL;
124 int ret=0,bit,bytes,mask;
137 buf=(unsigned char *)OPENSSL_malloc(bytes);
140 BNerr(BN_F_BNRAND,ERR_R_MALLOC_FAILURE);
144 /* make a random number and set the top and bottom bits */
146 RAND_add(&tim,sizeof(tim),0.0);
150 if (RAND_pseudo_bytes(buf, bytes) == -1)
155 if (RAND_bytes(buf, bytes) <= 0)
162 /* generate patterns that are more likely to trigger BN
167 for (i = 0; i < bytes; i++)
169 RAND_pseudo_bytes(&c, 1);
170 if (c >= 128 && i > 0)
191 buf[0]|=(3<<(bit-1));
200 if (bottom) /* set bottom bit if requested */
202 if (!BN_bin2bn(buf,bytes,rnd)) goto err;
207 OPENSSL_cleanse(buf,bytes);
214 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
216 return bnrand(0, rnd, bits, top, bottom);
219 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
221 return bnrand(1, rnd, bits, top, bottom);
225 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)
227 return bnrand(2, rnd, bits, top, bottom);
232 /* random number r: 0 <= r < range */
233 static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range)
235 int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_rand;
239 if (range->neg || BN_is_zero(range))
241 BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
245 n = BN_num_bits(range); /* n > 0 */
247 /* BN_is_bit_set(range, n - 1) always holds */
252 /* FIPS 186-3 is picky about how random numbers for keys etc are
253 * generated. So we just use the second case which is equivalent to
254 * "Generation by Testing Candidates" mentioned in B.1.2 et al.
256 else if (!FIPS_module_mode() && !BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3))
258 else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3))
262 * so 3*range (= 11..._2) is exactly one bit longer than range */
265 if (!bn_rand(r, n + 1, -1, 0)) return 0;
266 /* If r < 3*range, use r := r MOD range
267 * (which is either r, r - range, or r - 2*range).
268 * Otherwise, iterate once more.
269 * Since 3*range = 11..._2, each iteration succeeds with
270 * probability >= .75. */
271 if (BN_cmp(r ,range) >= 0)
273 if (!BN_sub(r, r, range)) return 0;
274 if (BN_cmp(r, range) >= 0)
275 if (!BN_sub(r, r, range)) return 0;
280 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
285 while (BN_cmp(r, range) >= 0);
291 /* range = 11..._2 or range = 101..._2 */
292 if (!bn_rand(r, n, -1, 0)) return 0;
296 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
300 while (BN_cmp(r, range) >= 0);
308 int BN_rand_range(BIGNUM *r, const BIGNUM *range)
310 return bn_rand_range(0, r, range);
313 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range)
315 return bn_rand_range(1, r, range);
318 #ifndef OPENSSL_NO_SHA512
319 /* BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike
320 * BN_rand_range, it also includes the contents of |priv| and |message| in the
321 * generation so that an RNG failure isn't fatal as long as |priv| remains
322 * secret. This is intended for use in DSA and ECDSA where an RNG weakness
323 * leads directly to private key exposure unless this function is used. */
324 int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM* priv,
325 const unsigned char *message, size_t message_len,
329 /* We use 512 bits of random data per iteration to
330 * ensure that we have at least |range| bits of randomness. */
331 unsigned char random_bytes[64];
332 unsigned char digest[SHA512_DIGEST_LENGTH];
334 /* We generate |range|+8 bytes of random output. */
335 const unsigned num_k_bytes = BN_num_bytes(range) + 8;
336 unsigned char private_bytes[96];
337 unsigned char *k_bytes;
340 k_bytes = OPENSSL_malloc(num_k_bytes);
344 /* We copy |priv| into a local buffer to avoid exposing its length. */
345 todo = sizeof(priv->d[0])*priv->top;
346 if (todo > sizeof(private_bytes))
348 /* No reasonable DSA or ECDSA key should have a private key
349 * this large and we don't handle this case in order to avoid
350 * leaking the length of the private key. */
351 BNerr(BN_F_BN_GENERATE_DSA_NONCE, BN_R_PRIVATE_KEY_TOO_LARGE);
354 memcpy(private_bytes, priv->d, todo);
355 memset(private_bytes + todo, 0, sizeof(private_bytes) - todo);
357 for (done = 0; done < num_k_bytes;) {
358 if (RAND_bytes(random_bytes, sizeof(random_bytes)) != 1)
361 SHA512_Update(&sha, &done, sizeof(done));
362 SHA512_Update(&sha, private_bytes, sizeof(private_bytes));
363 SHA512_Update(&sha, message, message_len);
364 SHA512_Update(&sha, random_bytes, sizeof(random_bytes));
365 SHA512_Final(digest, &sha);
367 todo = num_k_bytes - done;
368 if (todo > SHA512_DIGEST_LENGTH)
369 todo = SHA512_DIGEST_LENGTH;
370 memcpy(k_bytes + done, digest, todo);
374 if (!BN_bin2bn(k_bytes, num_k_bytes, out))
376 if (BN_mod(out, out, range, ctx) != 1)
382 OPENSSL_free(k_bytes);
385 #endif /* OPENSSL_NO_SHA512 */