rc5_skey.c revision 296341 
1/* crypto/rc5/rc5_skey.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
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.
8 *
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).
15 *
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.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
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)"
40 *
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
51 * SUCH DAMAGE.
52 *
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.]
57 */
58
59#include <openssl/rc5.h>
60#include "rc5_locl.h"
61
62void RC5_32_set_key(RC5_32_KEY *key, int len, const unsigned char *data,
63                    int rounds)
64{
65    RC5_32_INT L[64], l, ll, A, B, *S, k;
66    int i, j, m, c, t, ii, jj;
67
68    if ((rounds != RC5_16_ROUNDS) &&
69        (rounds != RC5_12_ROUNDS) && (rounds != RC5_8_ROUNDS))
70        rounds = RC5_16_ROUNDS;
71
72    key->rounds = rounds;
73    S = &(key->data[0]);
74    j = 0;
75    for (i = 0; i <= (len - 8); i += 8) {
76        c2l(data, l);
77        L[j++] = l;
78        c2l(data, l);
79        L[j++] = l;
80    }
81    ii = len - i;
82    if (ii) {
83        k = len & 0x07;
84        c2ln(data, l, ll, k);
85        L[j + 0] = l;
86        L[j + 1] = ll;
87    }
88
89    c = (len + 3) / 4;
90    t = (rounds + 1) * 2;
91    S[0] = RC5_32_P;
92    for (i = 1; i < t; i++)
93        S[i] = (S[i - 1] + RC5_32_Q) & RC5_32_MASK;
94
95    j = (t > c) ? t : c;
96    j *= 3;
97    ii = jj = 0;
98    A = B = 0;
99    for (i = 0; i < j; i++) {
100        k = (S[ii] + A + B) & RC5_32_MASK;
101        A = S[ii] = ROTATE_l32(k, 3);
102        m = (int)(A + B);
103        k = (L[jj] + A + B) & RC5_32_MASK;
104        B = L[jj] = ROTATE_l32(k, m);
105        if (++ii >= t)
106            ii = 0;
107        if (++jj >= c)
108            jj = 0;
109    }
110}
111