1 /* crypto/bn/bn_mod.c */
2 /* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
3 * for the OpenSSL project. */
4 /* ====================================================================
5 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
19 * 3. All advertising materials mentioning features or use of this
20 * software must display the following acknowledgment:
21 * "This product includes software developed by the OpenSSL Project
22 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
25 * endorse or promote products derived from this software without
26 * prior written permission. For written permission, please contact
27 * openssl-core@openssl.org.
29 * 5. Products derived from this software may not be called "OpenSSL"
30 * nor may "OpenSSL" appear in their names without prior written
31 * permission of the OpenSSL Project.
33 * 6. Redistributions of any form whatsoever must retain the following
35 * "This product includes software developed by the OpenSSL Project
36 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
39 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
40 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
41 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
42 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
47 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
48 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
49 * OF THE POSSIBILITY OF SUCH DAMAGE.
50 * ====================================================================
52 * This product includes cryptographic software written by Eric Young
53 * (eay@cryptsoft.com). This product includes software written by Tim
54 * Hudson (tjh@cryptsoft.com).
57 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
58 * All rights reserved.
60 * This package is an SSL implementation written
61 * by Eric Young (eay@cryptsoft.com).
62 * The implementation was written so as to conform with Netscapes SSL.
64 * This library is free for commercial and non-commercial use as long as
65 * the following conditions are aheared to. The following conditions
66 * apply to all code found in this distribution, be it the RC4, RSA,
67 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
68 * included with this distribution is covered by the same copyright terms
69 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
71 * Copyright remains Eric Young's, and as such any Copyright notices in
72 * the code are not to be removed.
73 * If this package is used in a product, Eric Young should be given attribution
74 * as the author of the parts of the library used.
75 * This can be in the form of a textual message at program startup or
76 * in documentation (online or textual) provided with the package.
78 * Redistribution and use in source and binary forms, with or without
79 * modification, are permitted provided that the following conditions
81 * 1. Redistributions of source code must retain the copyright
82 * notice, this list of conditions and the following disclaimer.
83 * 2. Redistributions in binary form must reproduce the above copyright
84 * notice, this list of conditions and the following disclaimer in the
85 * documentation and/or other materials provided with the distribution.
86 * 3. All advertising materials mentioning features or use of this software
87 * must display the following acknowledgement:
88 * "This product includes cryptographic software written by
89 * Eric Young (eay@cryptsoft.com)"
90 * The word 'cryptographic' can be left out if the rouines from the library
91 * being used are not cryptographic related :-).
92 * 4. If you include any Windows specific code (or a derivative thereof) from
93 * the apps directory (application code) you must include an acknowledgement:
94 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
96 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
97 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
98 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
99 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
100 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
101 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
102 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
103 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
104 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
105 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
108 * The licence and distribution terms for any publically available version or
109 * derivative of this code cannot be changed. i.e. this code cannot simply be
110 * copied and put under another distribution licence
111 * [including the GNU Public Licence.]
114 #include "cryptlib.h"
118 #if 0 /* now just a #define */
119 int BN_mod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
121 return(BN_div(NULL,rem,m,d,ctx));
122 /* note that rem->neg == m->neg (unless the remainder is zero) */
127 int BN_nnmod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
129 /* like BN_mod, but returns non-negative remainder
130 * (i.e., 0 <= rem < |d| always holds) */
132 if (!(BN_mod(rem,m,d,ctx)))
136 /* now -|d| < rem < 0, so we have to set rem := rem + |d| */
137 return (d->neg ? BN_sub : BN_add)(rem, rem, d);
141 int BN_mod_add(BIGNUM *ret, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, BN_CTX *ctx)
143 if (!BN_add(ret, a, b)) return 0;
144 return BN_nnmod(ret, ret, m, ctx);
148 int BN_mod_sub(BIGNUM *ret, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, BN_CTX *ctx)
150 if (!BN_sub(ret, a, b)) return 0;
151 return BN_nnmod(ret, ret, m, ctx);
156 int BN_mod_mul(BIGNUM *ret, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
167 if ((t = BN_CTX_get(ctx)) == NULL) goto err;
169 { if (!BN_sqr(t,a,ctx)) goto err; }
171 { if (!BN_mul(t,a,b,ctx)) goto err; }
172 if (!BN_nnmod(ret,t,m,ctx)) goto err;
180 int BN_mod_sqr(BIGNUM *ret, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx)
182 if (!BN_sqr(ret, a, ctx)) return 0;
183 /* ret->neg == 0, thus we don't need BN_nnmod */
184 return BN_mod(ret, ret, m, ctx);