crypto/des/qud_cksm.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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 /*
  11  * From "Message Authentication" R.R. Jueneman, S.M. Matyas, C.H. Meyer IEEE
  12  * Communications Magazine Sept 1985 Vol. 23 No. 9 p 29-40 This module in
  13  * only based on the code in this paper and is almost definitely not the same
  14  * as the MIT implementation.
  15  */
  16 #include "des_locl.h"
  17
  18 /* bug fix for dos - 7/6/91 - Larry hughes@logos.ucs.indiana.edu */
  19 #define Q_B0(a) (((DES_LONG)(a)))
  20 #define Q_B1(a) (((DES_LONG)(a))<<8)
  21 #define Q_B2(a) (((DES_LONG)(a))<<16)
  22 #define Q_B3(a) (((DES_LONG)(a))<<24)
  23
  24 /* used to scramble things a bit */
  25 /* Got the value MIT uses via brute force :-) 2/10/90 eay */
  26 #define NOISE   ((DES_LONG)83653421L)
  27
  28 DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],
  29                         long length, int out_count, DES_cblock *seed)
  30 {
  31     DES_LONG z0, z1, t0, t1;
  32     int i;
  33     long l;
  34     const unsigned char *cp;
  35     DES_LONG *lp;
  36
  37     if (out_count < 1)
  38         out_count = 1;
  39     lp = (DES_LONG *)&(output[0])[0];
  40
  41     z0 = Q_B0((*seed)[0]) | Q_B1((*seed)[1]) | Q_B2((*seed)[2]) |
  42         Q_B3((*seed)[3]);
  43     z1 = Q_B0((*seed)[4]) | Q_B1((*seed)[5]) | Q_B2((*seed)[6]) |
  44         Q_B3((*seed)[7]);
  45
  46     for (i = 0; ((i < 4) && (i < out_count)); i++) {
  47         cp = input;
  48         l = length;
  49         while (l > 0) {
  50             if (l > 1) {
  51                 t0 = (DES_LONG)(*(cp++));
  52                 t0 |= (DES_LONG)Q_B1(*(cp++));
  53                 l--;
  54             } else
  55                 t0 = (DES_LONG)(*(cp++));
  56             l--;
  57             /* add */
  58             t0 += z0;
  59             t0 &= 0xffffffffL;
  60             t1 = z1;
  61             /* square, well sort of square */
  62             z0 = ((((t0 * t0) & 0xffffffffL) + ((t1 * t1) & 0xffffffffL))
  63                   & 0xffffffffL) % 0x7fffffffL;
  64             z1 = ((t0 * ((t1 + NOISE) & 0xffffffffL)) & 0xffffffffL) %
  65                 0x7fffffffL;
  66         }
  67         if (lp != NULL) {
  68             /*
  69              * The MIT library assumes that the checksum is composed of
  70              * 2*out_count 32 bit ints
  71              */
  72             *lp++ = z0;
  73             *lp++ = z1;
  74         }
  75     }
  76     return (z0);
  77 }