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authorbeck <>2002-05-15 02:29:21 +0000
committerbeck <>2002-05-15 02:29:21 +0000
commitb64270d1e45fe7f3241e4c9b6ce60d5ac89bc2e9 (patch)
treefa27cf82a1250b64ed3bf5f4a18c7354d470bbcc /src/lib/libcrypto/aes/aes_ctr.c
parente471e1ea98d673597b182ea85f29e30c97cd08b5 (diff)
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OpenSSL 0.9.7 stable 2002 05 08 merge
Diffstat (limited to 'src/lib/libcrypto/aes/aes_ctr.c')
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1/* crypto/aes/aes_ctr.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#include <assert.h>
53#include <openssl/aes.h>
54#include "aes_locl.h"
55
56/* NOTE: CTR mode is big-endian. The rest of the AES code
57 * is endian-neutral. */
58
59/* increment counter (128-bit int) by 2^64 */
60static void AES_ctr128_inc(unsigned char *counter) {
61 unsigned long c;
62
63 /* Grab 3rd dword of counter and increment */
64#ifdef L_ENDIAN
65 c = GETU32(counter + 8);
66 c++;
67 PUTU32(counter + 8, c);
68#else
69 c = GETU32(counter + 4);
70 c++;
71 PUTU32(counter + 4, c);
72#endif
73
74 /* if no overflow, we're done */
75 if (c)
76 return;
77
78 /* Grab top dword of counter and increment */
79#ifdef L_ENDIAN
80 c = GETU32(counter + 12);
81 c++;
82 PUTU32(counter + 12, c);
83#else
84 c = GETU32(counter + 0);
85 c++;
86 PUTU32(counter + 0, c);
87#endif
88
89}
90
91/* The input encrypted as though 128bit counter mode is being
92 * used. The extra state information to record how much of the
93 * 128bit block we have used is contained in *num;
94 */
95void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out,
96 const unsigned long length, const AES_KEY *key,
97 unsigned char *counter, unsigned int *num) {
98
99 unsigned int n;
100 unsigned long l=length;
101 unsigned char tmp[AES_BLOCK_SIZE];
102
103 assert(in && out && key && counter && num);
104
105 n = *num;
106
107 while (l--) {
108 if (n == 0) {
109 AES_ctr128_inc(counter);
110 AES_encrypt(counter, tmp, key);
111 }
112 *(out++) = *(in++) ^ tmp[n];
113 n = (n+1) % AES_BLOCK_SIZE;
114 }
115
116 *num=n;
117}