2 * Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
3 * for the OpenSSL project.
5 /* ====================================================================
6 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@openssl.org.
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
58 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
59 * All rights reserved.
61 * This package is an SSL implementation written
62 * by Eric Young (eay@cryptsoft.com).
63 * The implementation was written so as to conform with Netscapes SSL.
65 * This library is free for commercial and non-commercial use as long as
66 * the following conditions are aheared to. The following conditions
67 * apply to all code found in this distribution, be it the RC4, RSA,
68 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
69 * included with this distribution is covered by the same copyright terms
70 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
72 * Copyright remains Eric Young's, and as such any Copyright notices in
73 * the code are not to be removed.
74 * If this package is used in a product, Eric Young should be given attribution
75 * as the author of the parts of the library used.
76 * This can be in the form of a textual message at program startup or
77 * in documentation (online or textual) provided with the package.
79 * Redistribution and use in source and binary forms, with or without
80 * modification, are permitted provided that the following conditions
82 * 1. Redistributions of source code must retain the copyright
83 * notice, this list of conditions and the following disclaimer.
84 * 2. Redistributions in binary form must reproduce the above copyright
85 * notice, this list of conditions and the following disclaimer in the
86 * documentation and/or other materials provided with the distribution.
87 * 3. All advertising materials mentioning features or use of this software
88 * must display the following acknowledgement:
89 * "This product includes cryptographic software written by
90 * Eric Young (eay@cryptsoft.com)"
91 * The word 'cryptographic' can be left out if the rouines from the library
92 * being used are not cryptographic related :-).
93 * 4. If you include any Windows specific code (or a derivative thereof) from
94 * the apps directory (application code) you must include an acknowledgement:
95 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
97 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
98 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
99 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
100 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
101 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
102 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
103 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
104 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
105 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
106 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
109 * The licence and distribution terms for any publically available version or
110 * derivative of this code cannot be changed. i.e. this code cannot simply be
111 * copied and put under another distribution licence
112 * [including the GNU Public Licence.]
115 #include "internal/cryptlib.h"
118 int BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
121 * like BN_mod, but returns non-negative remainder (i.e., 0 <= r < |d|
125 if (!(BN_mod(r, m, d, ctx)))
129 /* now -|d| < r < 0, so we have to set r := r + |d| */
130 return (d->neg ? BN_sub : BN_add) (r, r, d);
133 int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
136 if (!BN_add(r, a, b))
138 return BN_nnmod(r, r, m, ctx);
142 * BN_mod_add variant that may be used if both a and b are non-negative and
145 int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
148 if (!BN_uadd(r, a, b))
150 if (BN_ucmp(r, m) >= 0)
151 return BN_usub(r, r, m);
155 int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
158 if (!BN_sub(r, a, b))
160 return BN_nnmod(r, r, m, ctx);
164 * BN_mod_sub variant that may be used if both a and b are non-negative and
167 int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
170 if (!BN_sub(r, a, b))
173 return BN_add(r, r, m);
178 int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
189 if ((t = BN_CTX_get(ctx)) == NULL)
192 if (!BN_sqr(t, a, ctx))
195 if (!BN_mul(t, a, b, ctx))
198 if (!BN_nnmod(r, t, m, ctx))
207 int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx)
209 if (!BN_sqr(r, a, ctx))
211 /* r->neg == 0, thus we don't need BN_nnmod */
212 return BN_mod(r, r, m, ctx);
215 int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx)
217 if (!BN_lshift1(r, a))
220 return BN_nnmod(r, r, m, ctx);
224 * BN_mod_lshift1 variant that may be used if a is non-negative and less than
227 int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *m)
229 if (!BN_lshift1(r, a))
232 if (BN_cmp(r, m) >= 0)
233 return BN_sub(r, r, m);
237 int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m,
240 BIGNUM *abs_m = NULL;
243 if (!BN_nnmod(r, a, m, ctx))
253 ret = BN_mod_lshift_quick(r, r, n, (abs_m ? abs_m : m));
261 * BN_mod_lshift variant that may be used if a is non-negative and less than
264 int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m)
267 if (BN_copy(r, a) == NULL)
275 max_shift = BN_num_bits(m) - BN_num_bits(r);
279 BNerr(BN_F_BN_MOD_LSHIFT_QUICK, BN_R_INPUT_NOT_REDUCED);
287 if (!BN_lshift(r, r, max_shift))
291 if (!BN_lshift1(r, r))
296 /* BN_num_bits(r) <= BN_num_bits(m) */
298 if (BN_cmp(r, m) >= 0) {
299 if (!BN_sub(r, r, m))