crypto/des/qud_cksm.c

   1 /*
   2  * Copyright 1995-2020 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 /*
  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
  17 /*
  18  * DES low level APIs are deprecated for public use, but still ok for internal
  19  * use.
  20  */
  21 #include "internal/deprecated.h"
  22
  23 #include "des_local.h"
  24
  25 #define Q_B0(a) (((DES_LONG)(a)))
  26 #define Q_B1(a) (((DES_LONG)(a))<<8)
  27 #define Q_B2(a) (((DES_LONG)(a))<<16)
  28 #define Q_B3(a) (((DES_LONG)(a))<<24)
  29
  30 /* used to scramble things a bit */
  31 /* Got the value MIT uses via brute force :-) 2/10/90 eay */
  32 #define NOISE   ((DES_LONG)83653421L)
  33
  34 DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],
  35                         long length, int out_count, DES_cblock *seed)
  36 {
  37     DES_LONG z0, z1, t0, t1;
  38     int i;
  39     long l;
  40     const unsigned char *cp;
  41     DES_LONG *lp;
  42
  43     if (out_count < 1)
  44         out_count = 1;
  45     lp = (DES_LONG *)&(output[0])[0];
  46
  47     z0 = Q_B0((*seed)[0]) | Q_B1((*seed)[1]) | Q_B2((*seed)[2]) |
  48         Q_B3((*seed)[3]);
  49     z1 = Q_B0((*seed)[4]) | Q_B1((*seed)[5]) | Q_B2((*seed)[6]) |
  50         Q_B3((*seed)[7]);
  51
  52     for (i = 0; ((i < 4) && (i < out_count)); i++) {
  53         cp = input;
  54         l = length;
  55         while (l > 0) {
  56             if (l > 1) {
  57                 t0 = (DES_LONG)(*(cp++));
  58                 t0 |= (DES_LONG)Q_B1(*(cp++));
  59                 l--;
  60             } else
  61                 t0 = (DES_LONG)(*(cp++));
  62             l--;
  63             /* add */
  64             t0 += z0;
  65             t0 &= 0xffffffffL;
  66             t1 = z1;
  67             /* square, well sort of square */
  68             z0 = ((((t0 * t0) & 0xffffffffL) + ((t1 * t1) & 0xffffffffL))
  69                   & 0xffffffffL) % 0x7fffffffL;
  70             z1 = ((t0 * ((t1 + NOISE) & 0xffffffffL)) & 0xffffffffL) %
  71                 0x7fffffffL;
  72         }
  73         if (lp != NULL) {
  74             /*
  75              * The MIT library assumes that the checksum is composed of
  76              * 2*out_count 32 bit ints
  77              */
  78             *lp++ = z0;
  79             *lp++ = z1;
  80         }
  81     }
  82     return z0;
  83 }