1 /* $OpenBSD: cfb128.c,v 1.3 2014/06/12 15:49:30 deraadt Exp $ */
2 /* ====================================================================
3 * Copyright (c) 2008 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 * ====================================================================
52 #include <openssl/crypto.h>
53 #include "modes_lcl.h"
62 /* The input and output encrypted as though 128bit cfb 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;
66 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
67 size_t len, const void *key,
68 unsigned char ivec[16], int *num,
69 int enc, block128_f block)
77 #if !defined(OPENSSL_SMALL_FOOTPRINT)
78 if (16%sizeof(size_t) == 0) do { /* always true actually */
80 *(out++) = ivec[n] ^= *(in++);
84 #ifdef __STRICT_ALIGNMENT
85 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
89 (*block)(ivec, ivec, key);
90 for (; n<16; n+=sizeof(size_t)) {
92 *(size_t*)(ivec+n) ^= *(size_t*)(in+n);
100 (*block)(ivec, ivec, key);
102 out[n] = ivec[n] ^= in[n];
109 /* the rest would be commonly eliminated by x86* compiler */
113 (*block)(ivec, ivec, key);
115 out[l] = ivec[n] ^= in[l];
121 #if !defined(OPENSSL_SMALL_FOOTPRINT)
122 if (16%sizeof(size_t) == 0) do { /* always true actually */
125 *(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c;
129 #ifdef __STRICT_ALIGNMENT
130 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
134 (*block)(ivec, ivec, key);
135 for (; n<16; n+=sizeof(size_t)) {
136 size_t t = *(size_t*)(in+n);
137 *(size_t*)(out+n) = *(size_t*)(ivec+n) ^ t;
138 *(size_t*)(ivec+n) = t;
146 (*block)(ivec, ivec, key);
149 out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c;
156 /* the rest would be commonly eliminated by x86* compiler */
161 (*block)(ivec, ivec, key);
163 out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;
171 /* This expects a single block of size nbits for both in and out. Note that
172 it corrupts any extra bits in the last byte of out */
173 static void cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
174 int nbits,const void *key,
175 unsigned char ivec[16],int enc,
179 unsigned char ovec[16*2 + 1]; /* +1 because we dererefence (but don't use) one byte off the end */
181 if (nbits<=0 || nbits>128) return;
183 /* fill in the first half of the new IV with the current IV */
184 memcpy(ovec,ivec,16);
185 /* construct the new IV */
186 (*block)(ivec,ivec,key);
188 if (enc) /* encrypt the input */
189 for(n=0 ; n < num ; ++n)
190 out[n] = (ovec[16+n] = in[n] ^ ivec[n]);
191 else /* decrypt the input */
192 for(n=0 ; n < num ; ++n)
193 out[n] = (ovec[16+n] = in[n]) ^ ivec[n];
194 /* shift ovec left... */
198 memcpy(ivec,ovec+num,16);
200 for(n=0 ; n < 16 ; ++n)
201 ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem);
203 /* it is not necessary to cleanse ovec, since the IV is not secret */
206 /* N.B. This expects the input to be packed, MS bit first */
207 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
208 size_t bits, const void *key,
209 unsigned char ivec[16], int *num,
210 int enc, block128_f block)
213 unsigned char c[1],d[1];
215 for(n=0 ; n<bits ; ++n)
217 c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0;
218 cfbr_encrypt_block(c,d,1,key,ivec,enc,block);
219 out[n/8]=(out[n/8]&~(1 << (unsigned int)(7-n%8))) |
220 ((d[0]&0x80) >> (unsigned int)(n%8));
224 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
225 size_t length, const void *key,
226 unsigned char ivec[16], int *num,
227 int enc, block128_f block)
231 for(n=0 ; n<length ; ++n)
232 cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc,block);