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

   1 /* -*-c-*-
   2  *
   3  * $Id: des3.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Implementation of double- and triple-DES
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <assert.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include <mLib/bits.h>
  38
  39 #include "blkc.h"
  40 #include "des-base.h"
  41 #include "des.h"
  42 #include "des3.h"
  43 #include "gcipher.h"
  44
  45 /*----- Global variables --------------------------------------------------*/
  46
  47 const octet des3_keysz[] = { KSZ_SET, 21, 7, 8, 14, 16, 24, 0 };
  48
  49 /*----- Main code ---------------------------------------------------------*/
  50
  51 /* --- @des3_init@ --- *
  52  *
  53  * Arguments:   @des3_ctx *k@ = pointer to key block
  54  *              @const void *buf@ = pointer to key buffer
  55  *              @size_t sz@ = size of key material
  56  *
  57  * Returns:     ---
  58  *
  59  * Use:         Initializes a DES key buffer.  The key buffer may have length
  60  *              7, 8, 14, 16, 21, or 24.  These correspond to one, two or
  61  *              three DES keys, either packed or unpacked (i.e., still
  62  *              containing parity bits).
  63  */
  64
  65 void des3_init(des3_ctx *k, const void *buf, size_t sz)
  66 {
  67   size_t step;
  68   const octet *p = buf;
  69
  70   KSZ_ASSERT(des3, sz);
  71
  72   if (sz % 7 == 0)
  73     step = 7;
  74   else
  75     step = 8;
  76
  77   des_init(&k->a, p, step);
  78   if (sz > 8) p += step;
  79   des_init(&k->b, p, step);
  80   if (sz > 16) p += step; else p = buf;
  81   des_init(&k->c, p, step);
  82 }
  83
  84 /* --- @des3_eblk@, @des3_dblk@ --- *
  85  *
  86  * Arguments:   @const des3_ctx *k@ = pointer to key block
  87  *              @const uint32 s[2]@ = pointer to source block
  88  *              @uint32 d[2]@ = pointer to destination block
  89  *
  90  * Returns:     ---
  91  *
  92  * Use:         Low-level block encryption and decryption.
  93  */
  94
  95 void des3_eblk(const des3_ctx *k, const uint32 *s, uint32 *d)
  96 {
  97   uint32 x = s[0], y = s[1];
  98   DES_IP(x, y);
  99   DES_EBLK(k->a.k, x, y, x, y);
 100   DES_DBLK(k->b.k, x, y, x, y);
 101   DES_EBLK(k->c.k, x, y, x, y);
 102   DES_IPINV(x, y);
 103   d[0] = x, d[1] = y;
 104 }
 105
 106 void des3_dblk(const des3_ctx *k, const uint32 *s, uint32 *d)
 107 {
 108   uint32 x = s[0], y = s[1];
 109   DES_IP(x, y);
 110   DES_DBLK(k->c.k, x, y, x, y);
 111   DES_EBLK(k->b.k, x, y, x, y);
 112   DES_DBLK(k->a.k, x, y, x, y);
 113   DES_IPINV(x, y);
 114   d[0] = x, d[1] = y;
 115 }
 116
 117 BLKC_TEST(DES3, des3)
 118
 119 /*----- That's all, folks -------------------------------------------------*/