1 /* crypto/aes/aes_cfb.c -*- mode:C; c-file-style: "eay" -*- */
2 /* ====================================================================
3 * Copyright (c) 1998-2002 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 * ====================================================================
51 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
52 * All rights reserved.
54 * This package is an SSL implementation written
55 * by Eric Young (eay@cryptsoft.com).
56 * The implementation was written so as to conform with Netscapes SSL.
58 * This library is free for commercial and non-commercial use as long as
59 * the following conditions are aheared to. The following conditions
60 * apply to all code found in this distribution, be it the RC4, RSA,
61 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
62 * included with this distribution is covered by the same copyright terms
63 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
65 * Copyright remains Eric Young's, and as such any Copyright notices in
66 * the code are not to be removed.
67 * If this package is used in a product, Eric Young should be given attribution
68 * as the author of the parts of the library used.
69 * This can be in the form of a textual message at program startup or
70 * in documentation (online or textual) provided with the package.
72 * Redistribution and use in source and binary forms, with or without
73 * modification, are permitted provided that the following conditions
75 * 1. Redistributions of source code must retain the copyright
76 * notice, this list of conditions and the following disclaimer.
77 * 2. Redistributions in binary form must reproduce the above copyright
78 * notice, this list of conditions and the following disclaimer in the
79 * documentation and/or other materials provided with the distribution.
80 * 3. All advertising materials mentioning features or use of this software
81 * must display the following acknowledgement:
82 * "This product includes cryptographic software written by
83 * Eric Young (eay@cryptsoft.com)"
84 * The word 'cryptographic' can be left out if the rouines from the library
85 * being used are not cryptographic related :-).
86 * 4. If you include any Windows specific code (or a derivative thereof) from
87 * the apps directory (application code) you must include an acknowledgement:
88 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
90 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
91 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
92 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
93 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
94 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
95 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
96 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
97 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
98 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
99 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
102 * The licence and distribution terms for any publically available version or
103 * derivative of this code cannot be changed. i.e. this code cannot simply be
104 * copied and put under another distribution licence
105 * [including the GNU Public Licence.]
115 #include <openssl/aes.h>
116 #include "aes_locl.h"
120 * The input and output encrypted as though 128bit cfb mode is being used.
121 * The extra state information to record how much of the 128bit block we have
122 * used is contained in *num;
125 void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
126 const unsigned long length, const AES_KEY *key,
127 unsigned char *ivec, int *num, const int enc)
131 unsigned long l = length;
134 assert(in && out && key && ivec && num);
141 AES_encrypt(ivec, ivec, key);
143 ivec[n] = *(out++) = *(in++) ^ ivec[n];
144 n = (n + 1) % AES_BLOCK_SIZE;
149 AES_encrypt(ivec, ivec, key);
152 *(out++) = *(in++) ^ ivec[n];
154 n = (n + 1) % AES_BLOCK_SIZE;
162 * This expects a single block of size nbits for both in and out. Note that
163 * it corrupts any extra bits in the last byte of out
165 void AES_cfbr_encrypt_block(const unsigned char *in, unsigned char *out,
166 const int nbits, const AES_KEY *key,
167 unsigned char *ivec, const int enc)
170 unsigned char ovec[AES_BLOCK_SIZE * 2];
172 if (nbits <= 0 || nbits > 128)
175 /* fill in the first half of the new IV with the current IV */
176 memcpy(ovec, ivec, AES_BLOCK_SIZE);
177 /* construct the new IV */
178 AES_encrypt(ivec, ivec, key);
179 num = (nbits + 7) / 8;
180 if (enc) /* encrypt the input */
181 for (n = 0; n < num; ++n)
182 out[n] = (ovec[AES_BLOCK_SIZE + n] = in[n] ^ ivec[n]);
183 else /* decrypt the input */
184 for (n = 0; n < num; ++n)
185 out[n] = (ovec[AES_BLOCK_SIZE + n] = in[n]) ^ ivec[n];
186 /* shift ovec left... */
190 memcpy(ivec, ovec + num, AES_BLOCK_SIZE);
192 for (n = 0; n < AES_BLOCK_SIZE; ++n)
193 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
195 /* it is not necessary to cleanse ovec, since the IV is not secret */
198 /* N.B. This expects the input to be packed, MS bit first */
199 void AES_cfb1_encrypt(const unsigned char *in, unsigned char *out,
200 const unsigned long length, const AES_KEY *key,
201 unsigned char *ivec, int *num, const int enc)
204 unsigned char c[1], d[1];
206 assert(in && out && key && ivec && num);
209 for (n = 0; n < length; ++n) {
210 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
211 AES_cfbr_encrypt_block(c, d, 1, key, ivec, enc);
213 (out[n / 8] & ~(1 << (7 - n % 8))) | ((d[0] & 0x80) >> (n % 8));
217 void AES_cfb8_encrypt(const unsigned char *in, unsigned char *out,
218 const unsigned long length, const AES_KEY *key,
219 unsigned char *ivec, int *num, const int enc)
223 assert(in && out && key && ivec && num);
226 for (n = 0; n < length; ++n)
227 AES_cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc);