1 /* crypto/aes/aes_ofb.c -*- mode:C; c-file-style: "eay" -*- */
2 /* ====================================================================
3 * Copyright (c) 2002-2006 The OpenSSL Project. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
31 * 6. Redistributions of any form whatsoever must retain the following
33 * "This product includes software developed by the OpenSSL Project
34 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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 * ====================================================================
59 #include <openssl/aes.h>
62 #define STRICT_ALIGNMENT
63 #if defined(__i386) || defined(__i386__) || \
64 defined(__x86_64) || defined(__x86_64__) || \
65 defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64)
66 # undef STRICT_ALIGNMENT
69 /* The input and output encrypted as though 128bit ofb mode is being
70 * used. The extra state information to record how much of the
71 * 128bit block we have used is contained in *num;
73 void AES_ofb128_encrypt(const unsigned char *in, unsigned char *out,
74 unsigned long length, const AES_KEY *key,
75 unsigned char *ivec, int *num) {
80 assert(in && out && key && ivec && num);
84 #if !defined(OPENSSL_SMALL_FOOTPRINT)
85 if (AES_BLOCK_SIZE%sizeof(size_t) == 0) do { /* always true actually */
88 *(out++) = ivec[n] ^ *(in++);
90 if(!(n = (n + 1) % AES_BLOCK_SIZE))
94 #if defined(STRICT_ALIGNMENT)
95 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
98 while ((l + AES_BLOCK_SIZE) <= length) {
100 AES_encrypt(ivec, ivec, key);
101 for (i=0;i<AES_BLOCK_SIZE;i+=sizeof(size_t)) {
102 *(size_t*)(out+l+i) =
103 *(size_t*)(ivec+i) ^ *(size_t*)(in+l+i);
109 AES_encrypt(ivec, ivec, key);
110 do { out[l] = ivec[n] ^ in[l];
112 } while (l < length);
119 /* this code would be commonly eliminated by x86* compiler */
122 AES_encrypt(ivec, ivec, key);
124 out[l] = ivec[n] ^ in[l];
126 n = (n+1) % AES_BLOCK_SIZE;