c_enc.c revision 296465 
1/* crypto/cast/c_enc.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/cast.h>
60#include "cast_lcl.h"
61
62void CAST_encrypt(CAST_LONG *data, const CAST_KEY *key)
63{
64    register CAST_LONG l, r, t;
65    const register CAST_LONG *k;
66
67    k = &(key->data[0]);
68    l = data[0];
69    r = data[1];
70
71    E_CAST(0, k, l, r, +, ^, -);
72    E_CAST(1, k, r, l, ^, -, +);
73    E_CAST(2, k, l, r, -, +, ^);
74    E_CAST(3, k, r, l, +, ^, -);
75    E_CAST(4, k, l, r, ^, -, +);
76    E_CAST(5, k, r, l, -, +, ^);
77    E_CAST(6, k, l, r, +, ^, -);
78    E_CAST(7, k, r, l, ^, -, +);
79    E_CAST(8, k, l, r, -, +, ^);
80    E_CAST(9, k, r, l, +, ^, -);
81    E_CAST(10, k, l, r, ^, -, +);
82    E_CAST(11, k, r, l, -, +, ^);
83    if (!key->short_key) {
84        E_CAST(12, k, l, r, +, ^, -);
85        E_CAST(13, k, r, l, ^, -, +);
86        E_CAST(14, k, l, r, -, +, ^);
87        E_CAST(15, k, r, l, +, ^, -);
88    }
89
90    data[1] = l & 0xffffffffL;
91    data[0] = r & 0xffffffffL;
92}
93
94void CAST_decrypt(CAST_LONG *data, const CAST_KEY *key)
95{
96    register CAST_LONG l, r, t;
97    const register CAST_LONG *k;
98
99    k = &(key->data[0]);
100    l = data[0];
101    r = data[1];
102
103    if (!key->short_key) {
104        E_CAST(15, k, l, r, +, ^, -);
105        E_CAST(14, k, r, l, -, +, ^);
106        E_CAST(13, k, l, r, ^, -, +);
107        E_CAST(12, k, r, l, +, ^, -);
108    }
109    E_CAST(11, k, l, r, -, +, ^);
110    E_CAST(10, k, r, l, ^, -, +);
111    E_CAST(9, k, l, r, +, ^, -);
112    E_CAST(8, k, r, l, -, +, ^);
113    E_CAST(7, k, l, r, ^, -, +);
114    E_CAST(6, k, r, l, +, ^, -);
115    E_CAST(5, k, l, r, -, +, ^);
116    E_CAST(4, k, r, l, ^, -, +);
117    E_CAST(3, k, l, r, +, ^, -);
118    E_CAST(2, k, r, l, -, +, ^);
119    E_CAST(1, k, l, r, ^, -, +);
120    E_CAST(0, k, r, l, +, ^, -);
121
122    data[1] = l & 0xffffffffL;
123    data[0] = r & 0xffffffffL;
124}
125
126void CAST_cbc_encrypt(const unsigned char *in, unsigned char *out,
127                      long length, const CAST_KEY *ks, unsigned char *iv,
128                      int enc)
129{
130    register CAST_LONG tin0, tin1;
131    register CAST_LONG tout0, tout1, xor0, xor1;
132    register long l = length;
133    CAST_LONG tin[2];
134
135    if (enc) {
136        n2l(iv, tout0);
137        n2l(iv, tout1);
138        iv -= 8;
139        for (l -= 8; l >= 0; l -= 8) {
140            n2l(in, tin0);
141            n2l(in, tin1);
142            tin0 ^= tout0;
143            tin1 ^= tout1;
144            tin[0] = tin0;
145            tin[1] = tin1;
146            CAST_encrypt(tin, ks);
147            tout0 = tin[0];
148            tout1 = tin[1];
149            l2n(tout0, out);
150            l2n(tout1, out);
151        }
152        if (l != -8) {
153            n2ln(in, tin0, tin1, l + 8);
154            tin0 ^= tout0;
155            tin1 ^= tout1;
156            tin[0] = tin0;
157            tin[1] = tin1;
158            CAST_encrypt(tin, ks);
159            tout0 = tin[0];
160            tout1 = tin[1];
161            l2n(tout0, out);
162            l2n(tout1, out);
163        }
164        l2n(tout0, iv);
165        l2n(tout1, iv);
166    } else {
167        n2l(iv, xor0);
168        n2l(iv, xor1);
169        iv -= 8;
170        for (l -= 8; l >= 0; l -= 8) {
171            n2l(in, tin0);
172            n2l(in, tin1);
173            tin[0] = tin0;
174            tin[1] = tin1;
175            CAST_decrypt(tin, ks);
176            tout0 = tin[0] ^ xor0;
177            tout1 = tin[1] ^ xor1;
178            l2n(tout0, out);
179            l2n(tout1, out);
180            xor0 = tin0;
181            xor1 = tin1;
182        }
183        if (l != -8) {
184            n2l(in, tin0);
185            n2l(in, tin1);
186            tin[0] = tin0;
187            tin[1] = tin1;
188            CAST_decrypt(tin, ks);
189            tout0 = tin[0] ^ xor0;
190            tout1 = tin[1] ^ xor1;
191            l2nn(tout0, tout1, out, l + 8);
192            xor0 = tin0;
193            xor1 = tin1;
194        }
195        l2n(xor0, iv);
196        l2n(xor1, iv);
197    }
198    tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
199    tin[0] = tin[1] = 0;
200}
201