crypto/openssl-0.9/crypto/aes/aes_cfb.c

   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
 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 */
 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 */
 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
 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