1 /* crypto/aes/aes_cfb.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 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
52 * All rights reserved.
53 *
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.
57 *
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).
64 *
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.
71 *
72 * Redistribution and use in source and binary forms, with or without
73 * modification, are permitted provided that the following conditions
74 * are met:
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)"
89 *
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
100 * SUCH DAMAGE.
101 *
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.]
106 */
107
108 #ifndef AES_DEBUG
109 # ifndef NDEBUG
110 # define NDEBUG
111 # endif
112 #endif
113 #include <assert.h>
114
115 #include <openssl/aes.h>
116 #include "aes_locl.h"
117 #include "e_os.h"
118
119 /* The input and output encrypted as though 128bit cfb mode is being
120 * used. The extra state information to record how much of the
121 * 128bit block we have used is contained in *num;
122 */
123
AES_cfb128_encrypt(const unsigned char * in,unsigned char * out,const unsigned long length,const AES_KEY * key,unsigned char * ivec,int * num,const int enc)124 void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
125 const unsigned long length, const AES_KEY *key,
126 unsigned char *ivec, int *num, const int enc) {
127
128 unsigned int n;
129 unsigned long l = length;
130 unsigned char c;
131
132 assert(in && out && key && ivec && num);
133
134 n = *num;
135
136 if (enc) {
137 while (l--) {
138 if (n == 0) {
139 AES_encrypt(ivec, ivec, key);
140 }
141 ivec[n] = *(out++) = *(in++) ^ ivec[n];
142 n = (n+1) % AES_BLOCK_SIZE;
143 }
144 } else {
145 while (l--) {
146 if (n == 0) {
147 AES_encrypt(ivec, ivec, key);
148 }
149 c = *(in);
150 *(out++) = *(in++) ^ ivec[n];
151 ivec[n] = c;
152 n = (n+1) % AES_BLOCK_SIZE;
153 }
154 }
155
156 *num=n;
157 }
158
159 /* This expects a single block of size nbits for both in and out. Note that
160 it corrupts any extra bits in the last byte of out */
AES_cfbr_encrypt_block(const unsigned char * in,unsigned char * out,const int nbits,const AES_KEY * key,unsigned char * ivec,const int enc)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)
164 {
165 int n,rem,num;
166 unsigned char ovec[AES_BLOCK_SIZE*2];
167
168 if (nbits<=0 || nbits>128) return;
169
170 /* fill in the first half of the new IV with the current IV */
171 memcpy(ovec,ivec,AES_BLOCK_SIZE);
172 /* construct the new IV */
173 AES_encrypt(ivec,ivec,key);
174 num = (nbits+7)/8;
175 if (enc) /* encrypt the input */
176 for(n=0 ; n < num ; ++n)
177 out[n] = (ovec[AES_BLOCK_SIZE+n] = in[n] ^ ivec[n]);
178 else /* decrypt the input */
179 for(n=0 ; n < num ; ++n)
180 out[n] = (ovec[AES_BLOCK_SIZE+n] = in[n]) ^ ivec[n];
181 /* shift ovec left... */
182 rem = nbits%8;
183 num = nbits/8;
184 if(rem==0)
185 memcpy(ivec,ovec+num,AES_BLOCK_SIZE);
186 else
187 for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
188 ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem);
189
190 /* it is not necessary to cleanse ovec, since the IV is not secret */
191 }
192
193 /* N.B. This expects the input to be packed, MS bit first */
AES_cfb1_encrypt(const unsigned char * in,unsigned char * out,const unsigned long length,const AES_KEY * key,unsigned char * ivec,int * num,const int enc)194 void AES_cfb1_encrypt(const unsigned char *in, unsigned char *out,
195 const unsigned long length, const AES_KEY *key,
196 unsigned char *ivec, int *num, const int enc)
197 {
198 unsigned int n;
199 unsigned char c[1],d[1];
200
201 assert(in && out && key && ivec && num);
202 assert(*num == 0);
203
204 memset(out,0,(length+7)/8);
205 for(n=0 ; n < length ; ++n)
206 {
207 c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0;
208 AES_cfbr_encrypt_block(c,d,1,key,ivec,enc);
209 out[n/8]=(out[n/8]&~(1 << (7-n%8)))|((d[0]&0x80) >> (n%8));
210 }
211 }
212
AES_cfb8_encrypt(const unsigned char * in,unsigned char * out,const unsigned long length,const AES_KEY * key,unsigned char * ivec,int * num,const int enc)213 void AES_cfb8_encrypt(const unsigned char *in, unsigned char *out,
214 const unsigned long length, const AES_KEY *key,
215 unsigned char *ivec, int *num, const int enc)
216 {
217 unsigned int n;
218
219 assert(in && out && key && ivec && num);
220 assert(*num == 0);
221
222 for(n=0 ; n < length ; ++n)
223 AES_cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc);
224 }
225
226