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

   1 /* -*-c-*-
   2  *
   3  * $Id: des3.c,v 1.2 2000/06/17 10:52:32 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 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: des3.c,v $
  33  * Revision 1.2  2000/06/17 10:52:32  mdw
  34  * Support new key size interface.
  35  *
  36  * Revision 1.1  1999/09/03 08:41:11  mdw
  37  * Initial import.
  38  *
  39  */
  40
  41 /*----- Header files ------------------------------------------------------*/
  42
  43 #include <assert.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47
  48 #include <mLib/bits.h>
  49
  50 #include "blkc.h"
  51 #include "des-base.h"
  52 #include "des.h"
  53 #include "des3.h"
  54 #include "gcipher.h"
  55
  56 /*----- Global variables --------------------------------------------------*/
  57
  58 const octet des3_keysz[] = { KSZ_SET, 21, 7, 8, 14, 16, 24, 0 };
  59
  60 /*----- Main code ---------------------------------------------------------*/
  61
  62 /* --- @des3_init@ --- *
  63  *
  64  * Arguments:   @des3_ctx *k@ = pointer to key block
  65  *              @const void *buf@ = pointer to key buffer
  66  *              @size_t sz@ = size of key material
  67  *
  68  * Returns:     ---
  69  *
  70  * Use:         Initializes a DES key buffer.  The key buffer may have length
  71  *              7, 8, 14, 16, 21, or 24.  These correspond to one, two or
  72  *              three DES keys, either packed or unpacked (i.e., still
  73  *              containing parity bits).
  74  */
  75
  76 void des3_init(des3_ctx *k, const void *buf, size_t sz)
  77 {
  78   size_t step;
  79   const octet *p = buf;
  80
  81   KSZ_ASSERT(des3, sz);
  82
  83   if (sz % 7 == 0)
  84     step = 7;
  85   else
  86     step = 8;
  87
  88   des_init(&k->a, p, step);
  89   if (sz > 8) p += step;
  90   des_init(&k->b, p, step);
  91   if (sz > 16) p += step; else p = buf;
  92   des_init(&k->c, p, step);
  93 }
  94
  95 /* --- @des3_eblk@, @des3_dblk@ --- *
  96  *
  97  * Arguments:   @const des3_ctx *k@ = pointer to key block
  98  *              @const uint32 s[2]@ = pointer to source block
  99  *              @uint32 d[2]@ = pointer to destination block
 100  *
 101  * Returns:     ---
 102  *
 103  * Use:         Low-level block encryption and decryption.
 104  */
 105
 106 void des3_eblk(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_EBLK(k->a.k, x, y, x, y);
 111   DES_DBLK(k->b.k, x, y, x, y);
 112   DES_EBLK(k->c.k, x, y, x, y);
 113   DES_IPINV(x, y);
 114   d[0] = x, d[1] = y;
 115 }
 116
 117 void des3_dblk(const des3_ctx *k, const uint32 *s, uint32 *d)
 118 {
 119   uint32 x = s[0], y = s[1];
 120   DES_IP(x, y);
 121   DES_DBLK(k->c.k, x, y, x, y);
 122   DES_EBLK(k->b.k, x, y, x, y);
 123   DES_DBLK(k->a.k, x, y, x, y);
 124   DES_IPINV(x, y);
 125   d[0] = x, d[1] = y;
 126 }
 127
 128 BLKC_TEST(DES3, des3)
 129
 130 /*----- That's all, folks -------------------------------------------------*/