aes_cbc.c revision bdfb8ad83da0647e9b9a32792598e8ce7ba3ef4d 
1/* crypto/aes/aes_cbc.c -*- mode:C; c-file-style: "eay" -*- */
2/* ====================================================================
3 * Copyright (c) 1998-2002 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#ifndef AES_DEBUG
53# ifndef NDEBUG
54#  define NDEBUG
55# endif
56#endif
57#include <assert.h>
58
59#include <openssl/aes.h>
60#include "aes_locl.h"
61
62void AES_cbc_encrypt(const unsigned char *in, unsigned char *out,
63		     const unsigned long length, const AES_KEY *key,
64		     unsigned char *ivec, const int enc) {
65
66	unsigned long n;
67	unsigned long len = length;
68	unsigned char tmp[AES_BLOCK_SIZE];
69	const unsigned char *iv = ivec;
70
71	assert(in && out && key && ivec);
72	assert((AES_ENCRYPT == enc)||(AES_DECRYPT == enc));
73
74	if (AES_ENCRYPT == enc) {
75		while (len >= AES_BLOCK_SIZE) {
76			for(n=0; n < AES_BLOCK_SIZE; ++n)
77				out[n] = in[n] ^ iv[n];
78			AES_encrypt(out, out, key);
79			iv = out;
80			len -= AES_BLOCK_SIZE;
81			in += AES_BLOCK_SIZE;
82			out += AES_BLOCK_SIZE;
83		}
84		if (len) {
85			for(n=0; n < len; ++n)
86				out[n] = in[n] ^ iv[n];
87			for(n=len; n < AES_BLOCK_SIZE; ++n)
88				out[n] = iv[n];
89			AES_encrypt(out, out, key);
90			iv = out;
91		}
92		memcpy(ivec,iv,AES_BLOCK_SIZE);
93	} else if (in != out) {
94		while (len >= AES_BLOCK_SIZE) {
95			AES_decrypt(in, out, key);
96			for(n=0; n < AES_BLOCK_SIZE; ++n)
97				out[n] ^= iv[n];
98			iv = in;
99			len -= AES_BLOCK_SIZE;
100			in  += AES_BLOCK_SIZE;
101			out += AES_BLOCK_SIZE;
102		}
103		if (len) {
104			AES_decrypt(in,tmp,key);
105			for(n=0; n < len; ++n)
106				out[n] = tmp[n] ^ iv[n];
107			iv = in;
108		}
109		memcpy(ivec,iv,AES_BLOCK_SIZE);
110	} else {
111		while (len >= AES_BLOCK_SIZE) {
112			memcpy(tmp, in, AES_BLOCK_SIZE);
113			AES_decrypt(in, out, key);
114			for(n=0; n < AES_BLOCK_SIZE; ++n)
115				out[n] ^= ivec[n];
116			memcpy(ivec, tmp, AES_BLOCK_SIZE);
117			len -= AES_BLOCK_SIZE;
118			in += AES_BLOCK_SIZE;
119			out += AES_BLOCK_SIZE;
120		}
121		if (len) {
122			memcpy(tmp, in, AES_BLOCK_SIZE);
123			AES_decrypt(tmp, out, key);
124			for(n=0; n < len; ++n)
125				out[n] ^= ivec[n];
126			for(n=len; n < AES_BLOCK_SIZE; ++n)
127				out[n] = tmp[n];
128			memcpy(ivec, tmp, AES_BLOCK_SIZE);
129		}
130	}
131}
132