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   1 /* -*-c-*-
   2  *
   3  * $Id: des3.h,v 1.4 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 #ifndef CATACOMB_DES3_H
  31 #define CATACOMB_DES3_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Notes on double- and triple-DES -----------------------------------*
  38  *
  39  * The normal recommendation for using DES now is `triple DES'.
  40  * Conventionally, this involves an encrypt-decrypt-encrypt sequence,
  41  * although whether the first and last operations use the same key is
  42  * unfortunately not agreed upon.  This interface handles both cases (and the
  43  * single-key one too, although the simple @des@ calls are quicker for that).
  44  */
  45
  46 /*----- Header files ------------------------------------------------------*/
  47
  48 #include <stddef.h>
  49
  50 #include <mLib/bits.h>
  51
  52 #ifndef CATACOMB_DES_H
  53 #  include "des.h"
  54 #endif
  55
  56 /*----- Magical numbers ---------------------------------------------------*/
  57
  58 #define DES3_BLKSZ 8
  59 #define DES3_KEYSZ 21
  60 #define DES3_CLASS (N, B, 64)
  61
  62 extern const octet des3_keysz[];
  63
  64 /*----- Data structures ---------------------------------------------------*/
  65
  66 typedef struct des3_ctx {
  67   des_ctx a, b, c;
  68 } des3_ctx;
  69
  70 /*----- Functions provided ------------------------------------------------*/
  71
  72 /* --- @des3_init@ --- *
  73  *
  74  * Arguments:   @des3_ctx *k@ = pointer to key block
  75  *              @const void *buf@ = pointer to key buffer
  76  *              @size_t sz@ = size of key material
  77  *
  78  * Returns:     ---
  79  *
  80  * Use:         Initializes a DES key buffer.  The key buffer may have length
  81  *              7, 8, 14, 16, 21, or 24.  These correspond to one, two or
  82  *              three DES keys, either packed or unpacked (i.e., still
  83  *              containing parity bits).
  84  */
  85
  86 extern void des3_init(des3_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
  87
  88 /* --- @des3_eblk@, @des_dblk@ --- *
  89  *
  90  * Arguments:   @const des3_ctx *k@ = pointer to key block
  91  *              @const uint32 s[2]@ = pointer to source block
  92  *              @uint32 d[2]@ = pointer to destination block
  93  *
  94  * Returns:     ---
  95  *
  96  * Use:         Low-level block encryption and decryption.
  97  */
  98
  99 extern void des3_eblk(const des3_ctx */*k*/,
 100                       const uint32 */*s*/, uint32 */*d*/);
 101 extern void des3_dblk(const des3_ctx */*k*/,
 102                       const uint32 */*s*/, uint32 */*d*/);
 103
 104 /*----- That's all, folks -------------------------------------------------*/
 105
 106 #ifdef __cplusplus
 107   }
 108 #endif
 109
 110 #endif