1 /* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * openssl-core@openssl.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 */
50
51 #include <openssl/crypto.h>
52 #include "modes_lcl.h"
53 #include <string.h>
54
55 #ifndef MODES_DEBUG
56 # ifndef NDEBUG
57 # define NDEBUG
58 # endif
59 #endif
60 #include <assert.h>
61
62 /* The input and output encrypted as though 128bit ofb mode is being
63 * used. The extra state information to record how much of the
64 * 128bit block we have used is contained in *num;
65 */
66 void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
67 size_t len, const void *key,
68 unsigned char ivec[16], int *num,
69 block128_f block)
70 {
71 unsigned int n;
72 size_t l=0;
73
74 assert(in && out && key && ivec && num);
75
76 n = *num;
77
78 #if !defined(OPENSSL_SMALL_FOOTPRINT)
79 if (16%sizeof(size_t) == 0) do { /* always true actually */
80 while (n && len) {
81 *(out++) = *(in++) ^ ivec[n];
82 --len;
83 n = (n+1) % 16;
84 }
85 #if defined(STRICT_ALIGNMENT)
86 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
87 break;
88 #endif
89 while (len>=16) {
90 (*block)(ivec, ivec, key);
91 for (; n<16; n+=sizeof(size_t))
92 *(size_t*)(out+n) =
93 *(size_t*)(in+n) ^ *(size_t*)(ivec+n);
94 len -= 16;
95 out += 16;
96 in += 16;
97 n = 0;
98 }
99 if (len) {
100 (*block)(ivec, ivec, key);
101 while (len--) {
102 out[n] = in[n] ^ ivec[n];
103 ++n;
104 }
105 }
106 *num = n;
107 return;
108 } while(0);
109 /* the rest would be commonly eliminated by x86* compiler */
110 #endif
111 while (l<len) {
112 if (n==0) {
113 (*block)(ivec, ivec, key);
114 }
115 out[l] = in[l] ^ ivec[n];
116 ++l;
117 n = (n+1) % 16;
118 }
119
120 *num=n;
121 }