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"
118 /* The input and output encrypted as though 128bit cfb mode is being
119 * used. The extra state information to record how much of the
120 * 128bit block we have used is contained in *num;
123 void AES_cfb128_encrypt(const unsigned char *in
, unsigned char *out
,
124 const unsigned long length
, const AES_KEY
*key
,
125 unsigned char *ivec
, int *num
, const int enc
) {
128 unsigned long l
= length
;
131 assert(in
&& out
&& key
&& ivec
&& num
);
138 AES_encrypt(ivec
, ivec
, key
);
140 ivec
[n
] = *(out
++) = *(in
++) ^ ivec
[n
];
141 n
= (n
+1) % AES_BLOCK_SIZE
;
146 AES_encrypt(ivec
, ivec
, key
);
149 *(out
++) = *(in
++) ^ ivec
[n
];
151 n
= (n
+1) % AES_BLOCK_SIZE
;
158 /* This expects a single block of size nbits for both in and out. Note that
159 it corrupts any extra bits in the last byte of out */
160 /* Untested, once it is working, it will be optimised */
161 void AES_cfbr_encrypt_block(const unsigned char *in
,unsigned char *out
,
162 const int nbits
,const AES_KEY
*key
,
163 unsigned char *ivec
,const int enc
)
166 unsigned char ovec
[AES_BLOCK_SIZE
*2];
168 assert(in
&& out
&& key
&& ivec
);
171 /* construct the new IV */
172 AES_encrypt(ivec
,ovec
,key
);
173 /* encrypt the input */
174 for(n
=0 ; n
< (nbits
+7)/8 ; ++n
)
175 out
[n
]=in
[n
]^ovec
[n
];
176 /* fill in the first half of the new IV with the current IV */
177 memcpy(ovec
,ivec
,AES_BLOCK_SIZE
);
178 /* and put the ciphertext in the second half */
179 memcpy(ovec
+AES_BLOCK_SIZE
,out
,(nbits
+7)/8);
180 /* shift ovec left most of the bits... */
181 memmove(ovec
,ovec
+nbits
/8,AES_BLOCK_SIZE
+(nbits
%8 ? 1 : 0));
182 /* now the remaining bits */
184 for(n
=0 ; n
< AES_BLOCK_SIZE
; ++n
)
187 ovec
[n
]|=ovec
[n
+1]>>(8-nbits
%8);
189 /* finally, move it back into place */
190 memcpy(ivec
,ovec
,AES_BLOCK_SIZE
);
194 /* construct the new IV in the first half of ovec */
195 AES_encrypt(ivec
,ovec
,key
);
196 /* decrypt the input */
197 for(n
=0 ; n
< (nbits
+7)/8 ; ++n
)
198 out
[n
]=in
[n
]^ovec
[n
];
199 /* fill in the first half of the new IV with the current IV */
200 memcpy(ovec
,ivec
,AES_BLOCK_SIZE
);
201 /* append the ciphertext */
202 memcpy(ovec
+AES_BLOCK_SIZE
,in
,(nbits
+7)/8);
203 /* shift ovec left most of the bits... */
204 memmove(ovec
,ovec
+nbits
/8,AES_BLOCK_SIZE
+(nbits
%8 ? 1 : 0));
205 /* now the remaining bits */
207 for(n
=0 ; n
< AES_BLOCK_SIZE
; ++n
)
210 ovec
[n
]|=ovec
[n
+1]>>(8-nbits
%8);
212 /* finally, move it back into place */
213 memcpy(ivec
,ovec
,AES_BLOCK_SIZE
);
215 /* it is not necessary to cleanse ovec, since the IV is not secret */
218 /* N.B. This expects the input to be packed, MS bit first */
219 void AES_cfb1_encrypt(const unsigned char *in
, unsigned char *out
,
220 const unsigned long length
, const AES_KEY
*key
,
221 unsigned char *ivec
, int *num
, const int enc
)
224 unsigned char c
[1],d
[1];
226 assert(in
&& out
&& key
&& ivec
&& num
);
229 memset(out
,0,(length
+7)/8);
230 for(n
=0 ; n
< length
; ++n
)
232 c
[0]=(in
[n
/8]&(1 << (7-n
%8))) ? 0x80 : 0;
233 AES_cfbr_encrypt_block(c
,d
,1,key
,ivec
,enc
);
234 out
[n
/8]=(out
[n
/8]&~(1 << (7-n
%8)))|((d
[0]&0x80) >> (n
%8));
238 void AES_cfb8_encrypt(const unsigned char *in
, unsigned char *out
,
239 const unsigned long length
, const AES_KEY
*key
,
240 unsigned char *ivec
, int *num
, const int enc
)
244 assert(in
&& out
&& key
&& ivec
&& num
);
247 for(n
=0 ; n
< length
; ++n
)
248 AES_cfbr_encrypt_block(&in
[n
],&out
[n
],8,key
,ivec
,enc
);