seed_cbc.c revision 296465 
1/* crypto/seed/seed_cbc.c -*- mode:C; c-file-style: "eay" -*- */
2/* ====================================================================
3 * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in
14 *    the documentation and/or other materials provided with the
15 *    distribution.
16 *
17 * 3. All advertising materials mentioning features or use of this
18 *    software must display the following acknowledgment:
19 *    "This product includes software developed by the OpenSSL Project
20 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21 *
22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23 *    endorse or promote products derived from this software without
24 *    prior written permission. For written permission, please contact
25 *    openssl-core@openssl.org.
26 *
27 * 5. Products derived from this software may not be called "OpenSSL"
28 *    nor may "OpenSSL" appear in their names without prior written
29 *    permission of the OpenSSL Project.
30 *
31 * 6. Redistributions of any form whatsoever must retain the following
32 *    acknowledgment:
33 *    "This product includes software developed by the OpenSSL Project
34 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47 * OF THE POSSIBILITY OF SUCH DAMAGE.
48 * ====================================================================
49 *
50 */
51
52#include "seed_locl.h"
53#include <string.h>
54
55void SEED_cbc_encrypt(const unsigned char *in, unsigned char *out,
56                      size_t len, const SEED_KEY_SCHEDULE *ks,
57                      unsigned char ivec[SEED_BLOCK_SIZE], int enc)
58{
59    size_t n;
60    unsigned char tmp[SEED_BLOCK_SIZE];
61    const unsigned char *iv = ivec;
62
63    if (enc) {
64        while (len >= SEED_BLOCK_SIZE) {
65            for (n = 0; n < SEED_BLOCK_SIZE; ++n)
66                out[n] = in[n] ^ iv[n];
67            SEED_encrypt(out, out, ks);
68            iv = out;
69            len -= SEED_BLOCK_SIZE;
70            in += SEED_BLOCK_SIZE;
71            out += SEED_BLOCK_SIZE;
72        }
73        if (len) {
74            for (n = 0; n < len; ++n)
75                out[n] = in[n] ^ iv[n];
76            for (n = len; n < SEED_BLOCK_SIZE; ++n)
77                out[n] = iv[n];
78            SEED_encrypt(out, out, ks);
79            iv = out;
80        }
81        memcpy(ivec, iv, SEED_BLOCK_SIZE);
82    } else if (in != out) {     /* decrypt */
83        while (len >= SEED_BLOCK_SIZE) {
84            SEED_decrypt(in, out, ks);
85            for (n = 0; n < SEED_BLOCK_SIZE; ++n)
86                out[n] ^= iv[n];
87            iv = in;
88            len -= SEED_BLOCK_SIZE;
89            in += SEED_BLOCK_SIZE;
90            out += SEED_BLOCK_SIZE;
91        }
92        if (len) {
93            SEED_decrypt(in, tmp, ks);
94            for (n = 0; n < len; ++n)
95                out[n] = tmp[n] ^ iv[n];
96            iv = in;
97        }
98        memcpy(ivec, iv, SEED_BLOCK_SIZE);
99    } else {                    /* decrypt, overlap */
100
101        while (len >= SEED_BLOCK_SIZE) {
102            memcpy(tmp, in, SEED_BLOCK_SIZE);
103            SEED_decrypt(in, out, ks);
104            for (n = 0; n < SEED_BLOCK_SIZE; ++n)
105                out[n] ^= ivec[n];
106            memcpy(ivec, tmp, SEED_BLOCK_SIZE);
107            len -= SEED_BLOCK_SIZE;
108            in += SEED_BLOCK_SIZE;
109            out += SEED_BLOCK_SIZE;
110        }
111        if (len) {
112            memcpy(tmp, in, SEED_BLOCK_SIZE);
113            SEED_decrypt(tmp, tmp, ks);
114            for (n = 0; n < len; ++n)
115                out[n] = tmp[n] ^ ivec[n];
116            memcpy(ivec, tmp, SEED_BLOCK_SIZE);
117        }
118    }
119}
120