crypto/external/bsd/openssl/lib/libdes/oofb_enc.c

   1 /* crypto/des/ofb_enc.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   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@cryptsoft.com).
  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@cryptsoft.com)"
  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@cryptsoft.com)"
  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_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
  68              long length, des_key_schedule schedule, des_cblock *ivec)
  69         {
  70         register DES_LONG d0,d1,vv0,vv1,v0,v1,n=(numbits+7)/8;
  71         register DES_LONG mask0,mask1;
  72         register long l=length;
  73         register int num=numbits;
  74         DES_LONG ti[2];
  75         unsigned char *iv;
  76
  77         if (num > 64) return;
  78         if (num > 32)
  79                 {
  80                 mask0=0xffffffffL;
  81                 if (num >= 64)
  82                         mask1=mask0;
  83                 else
  84                         mask1=(1L<<(num-32))-1;
  85                 }
  86         else
  87                 {
  88                 if (num == 32)
  89                         mask0=0xffffffffL;
  90                 else
  91                         mask0=(1L<<num)-1;
  92                 mask1=0x00000000L;
  93                 }
  94
  95         iv = &(*ivec)[0];
  96         c2l(iv,v0);
  97         c2l(iv,v1);
  98         ti[0]=v0;
  99         ti[1]=v1;
 100         while (l-- > 0)
 101                 {
 102                 ti[0]=v0;
 103                 ti[1]=v1;
 104                 des_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
 105                 vv0=ti[0];
 106                 vv1=ti[1];
 107                 c2ln(in,d0,d1,n);
 108                 in+=n;
 109                 d0=(d0^vv0)&mask0;
 110                 d1=(d1^vv1)&mask1;
 111                 l2cn(d0,d1,out,n);
 112                 out+=n;
 113
 114                 if (num == 32)
 115                         { v0=v1; v1=vv0; }
 116                 else if (num == 64)
 117                                 { v0=vv0; v1=vv1; }
 118                 else if (num > 32) /* && num != 64 */
 119                         {
 120                         v0=((v1>>(num-32))|(vv0<<(64-num)))&0xffffffffL;
 121                         v1=((vv0>>(num-32))|(vv1<<(64-num)))&0xffffffffL;
 122                         }
 123                 else /* num < 32 */
 124                         {
 125                         v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
 126                         v1=((v1>>num)|(vv0<<(32-num)))&0xffffffffL;
 127                         }
 128                 }
 129         iv = &(*ivec)[0];
 130         l2c(v0,iv);
 131         l2c(v1,iv);
 132         v0=v1=d0=d1=ti[0]=ti[1]=vv0=vv1=0;
 133         }
 134