crypto/des/cbc_cksm.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include "des_locl.h"
  11
  12 DES_LONG DES_cbc_cksum(const unsigned char *in, DES_cblock *output,
  13                        long length, DES_key_schedule *schedule,
  14                        const_DES_cblock *ivec)
  15 {
  16     register DES_LONG tout0, tout1, tin0, tin1;
  17     register long l = length;
  18     DES_LONG tin[2];
  19     unsigned char *out = &(*output)[0];
  20     const unsigned char *iv = &(*ivec)[0];
  21
  22     c2l(iv, tout0);
  23     c2l(iv, tout1);
  24     for (; l > 0; l -= 8) {
  25         if (l >= 8) {
  26             c2l(in, tin0);
  27             c2l(in, tin1);
  28         } else
  29             c2ln(in, tin0, tin1, l);
  30
  31         tin0 ^= tout0;
  32         tin[0] = tin0;
  33         tin1 ^= tout1;
  34         tin[1] = tin1;
  35         DES_encrypt1((DES_LONG *)tin, schedule, DES_ENCRYPT);
  36         tout0 = tin[0];
  37         tout1 = tin[1];
  38     }
  39     if (out != NULL) {
  40         l2c(tout0, out);
  41         l2c(tout1, out);
  42     }
  43     tout0 = tin0 = tin1 = tin[0] = tin[1] = 0;
  44     /*
  45      * Transform the data in tout1 so that it will match the return value
  46      * that the MIT Kerberos mit_des_cbc_cksum API returns.
  47      */
  48     tout1 = ((tout1 >> 24L) & 0x000000FF)
  49         | ((tout1 >> 8L) & 0x0000FF00)
  50         | ((tout1 << 8L) & 0x00FF0000)
  51         | ((tout1 << 24L) & 0xFF000000);
  52     return tout1;
  53 }