crypto/heimdal-0.6.3/lib/des/cfb_enc.c

   1 /* crypto/des/cfb_enc.c */
   2 /* Copyright (C) 1995-1997 Eric Young (eay@mincom.oz.au)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@mincom.oz.au).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@mincom.oz.au).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@mincom.oz.au)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@mincom.oz.au)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include "des_locl.h"
  60
  61 /* The input and output are loaded in multiples of 8 bits.
  62  * What this means is that if you hame numbits=12 and length=2
  63  * the first 12 bits will be retrieved from the first byte and half
  64  * the second.  The second 12 bits will come from the 3rd and half the 4th
  65  * byte.
  66  */
  67 void des_cfb_encrypt(in, out, numbits, length, schedule, ivec, encrypt)
  68 unsigned char *in;
  69 unsigned char *out;
  70 int numbits;
  71 long length;
  72 des_key_schedule schedule;
  73 des_cblock (*ivec);
  74 int encrypt;
  75         {
  76         register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8;
  77         register DES_LONG mask0,mask1;
  78         register unsigned long l=length;
  79         register int num=numbits;
  80         DES_LONG ti[2];
  81         unsigned char *iv;
  82
  83         if (num > 64) return;
  84         if (num > 32)
  85                 {
  86                 mask0=0xffffffffL;
  87                 if (num == 64)
  88                         mask1=mask0;
  89                 else    mask1=(1L<<(num-32))-1;
  90                 }
  91         else
  92                 {
  93                 if (num == 32)
  94                         mask0=0xffffffffL;
  95                 else    mask0=(1L<<num)-1;
  96                 mask1=0x00000000;
  97                 }
  98
  99         iv=(unsigned char *)ivec;
 100         c2l(iv,v0);
 101         c2l(iv,v1);
 102         if (encrypt)
 103                 {
 104                 while (l >= n)
 105                         {
 106                         l-=n;
 107                         ti[0]=v0;
 108                         ti[1]=v1;
 109                         des_encrypt((DES_LONG *)ti,schedule,DES_ENCRYPT);
 110                         c2ln(in,d0,d1,n);
 111                         in+=n;
 112                         d0=(d0^ti[0])&mask0;
 113                         d1=(d1^ti[1])&mask1;
 114                         l2cn(d0,d1,out,n);
 115                         out+=n;
 116                         /* 30-08-94 - eay - changed because l>>32 and
 117                          * l<<32 are bad under gcc :-( */
 118                         if (num == 32)
 119                                 { v0=v1; v1=d0; }
 120                         else if (num == 64)
 121                                 { v0=d0; v1=d1; }
 122                         else if (num > 32) /* && num != 64 */
 123                                 {
 124                                 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
 125                                 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
 126                                 }
 127                         else /* num < 32 */
 128                                 {
 129                                 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
 130                                 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
 131                                 }
 132                         }
 133                 }
 134         else
 135                 {
 136                 while (l >= n)
 137                         {
 138                         l-=n;
 139                         ti[0]=v0;
 140                         ti[1]=v1;
 141                         des_encrypt((DES_LONG *)ti,schedule,DES_ENCRYPT);
 142                         c2ln(in,d0,d1,n);
 143                         in+=n;
 144                         /* 30-08-94 - eay - changed because l>>32 and
 145                          * l<<32 are bad under gcc :-( */
 146                         if (num == 32)
 147                                 { v0=v1; v1=d0; }
 148                         else if (num == 64)
 149                                 { v0=d0; v1=d1; }
 150                         else if (num > 32) /* && num != 64 */
 151                                 {
 152                                 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
 153                                 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
 154                                 }
 155                         else /* num < 32 */
 156                                 {
 157                                 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
 158                                 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
 159                                 }
 160                         d0=(d0^ti[0])&mask0;
 161                         d1=(d1^ti[1])&mask1;
 162                         l2cn(d0,d1,out,n);
 163                         out+=n;
 164                         }
 165                 }
 166         iv=(unsigned char *)ivec;
 167         l2c(v0,iv);
 168         l2c(v1,iv);
 169         v0=v1=d0=d1=ti[0]=ti[1]=0;
 170         }
 171