aes_cfb.c revision 98d58bb80c64b02a33662f0ea80351d4a1535267
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 124void 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 */ 161void 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 */ 194void 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 for(n=0 ; n < length ; ++n) 205 { 206 c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0; 207 AES_cfbr_encrypt_block(c,d,1,key,ivec,enc); 208 out[n/8]=(out[n/8]&~(1 << (7-n%8)))|((d[0]&0x80) >> (n%8)); 209 } 210 } 211 212void AES_cfb8_encrypt(const unsigned char *in, unsigned char *out, 213 const unsigned long length, const AES_KEY *key, 214 unsigned char *ivec, int *num, const int enc) 215 { 216 unsigned int n; 217 218 assert(in && out && key && ivec && num); 219 assert(*num == 0); 220 221 for(n=0 ; n < length ; ++n) 222 AES_cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc); 223 } 224 225