git.distorted.org.uk Git - u/mdw/catacomb/blob - symm/des3.c

   1 /* -*-c-*-
   2  *
   3  * Implementation of double- and triple-DES
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <assert.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <mLib/bits.h>
  36
  37 #include "blkc.h"
  38 #include "des-base.h"
  39 #include "des.h"
  40 #include "des3.h"
  41 #include "gcipher.h"
  42
  43 /*----- Global variables --------------------------------------------------*/
  44
  45 const octet des3_keysz[] = { KSZ_SET, 21, 7, 8, 14, 16, 24, 0 };
  46
  47 /*----- Main code ---------------------------------------------------------*/
  48
  49 /* --- @des3_init@ --- *
  50  *
  51  * Arguments:   @des3_ctx *k@ = pointer to key block
  52  *              @const void *buf@ = pointer to key buffer
  53  *              @size_t sz@ = size of key material
  54  *
  55  * Returns:     ---
  56  *
  57  * Use:         Initializes a DES key buffer.  The key buffer may have length
  58  *              7, 8, 14, 16, 21, or 24.  These correspond to one, two or
  59  *              three DES keys, either packed or unpacked (i.e., still
  60  *              containing parity bits).
  61  */
  62
  63 void des3_init(des3_ctx *k, const void *buf, size_t sz)
  64 {
  65   size_t step;
  66   const octet *p = buf;
  67
  68   KSZ_ASSERT(des3, sz);
  69
  70   if (sz % 7 == 0)
  71     step = 7;
  72   else
  73     step = 8;
  74
  75   des_init(&k->a, p, step);
  76   if (sz > 8) p += step;
  77   des_init(&k->b, p, step);
  78   if (sz > 16) p += step; else p = buf;
  79   des_init(&k->c, p, step);
  80 }
  81
  82 /* --- @des3_eblk@, @des3_dblk@ --- *
  83  *
  84  * Arguments:   @const des3_ctx *k@ = pointer to key block
  85  *              @const uint32 s[2]@ = pointer to source block
  86  *              @uint32 d[2]@ = pointer to destination block
  87  *
  88  * Returns:     ---
  89  *
  90  * Use:         Low-level block encryption and decryption.
  91  */
  92
  93 void des3_eblk(const des3_ctx *k, const uint32 *s, uint32 *d)
  94 {
  95   uint32 x = s[0], y = s[1];
  96   DES_IP(x, y);
  97   DES_EBLK(k->a.k, x, y, x, y);
  98   DES_DBLK(k->b.k, x, y, x, y);
  99   DES_EBLK(k->c.k, x, y, x, y);
 100   DES_IPINV(x, y);
 101   d[0] = x, d[1] = y;
 102 }
 103
 104 void des3_dblk(const des3_ctx *k, const uint32 *s, uint32 *d)
 105 {
 106   uint32 x = s[0], y = s[1];
 107   DES_IP(x, y);
 108   DES_DBLK(k->c.k, x, y, x, y);
 109   DES_EBLK(k->b.k, x, y, x, y);
 110   DES_DBLK(k->a.k, x, y, x, y);
 111   DES_IPINV(x, y);
 112   d[0] = x, d[1] = y;
 113 }
 114
 115 BLKC_TEST(DES3, des3)
 116
 117 /*----- That's all, folks -------------------------------------------------*/