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   1 /* -*-c-*-
   2  *
   3  * $Id: des.h,v 1.3 2000/06/17 10:52:32 mdw Exp $
   4  *
   5  * The Data Encryption Standard
   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: des.h,v $
  33  * Revision 1.3  2000/06/17 10:52:32  mdw
  34  * Support new key size interface.
  35  *
  36  * Revision 1.2  1999/12/10 23:29:48  mdw
  37  * Change header file guard names.
  38  *
  39  * Revision 1.1  1999/09/03 08:41:11  mdw
  40  * Initial import.
  41  *
  42  */
  43
  44 /*----- Notes on the Data Encryption Standard -----------------------------*
  45  *
  46  * Almost twenty years after it was first accepted, DES is still the standard
  47  * block cipher.  It's showing its age in its small key size and poor
  48  * optimiziation for software implementations, but it's not really been badly
  49  * dented by the intensive analysis thrown at it.
  50  *
  51  * This interface is here for compatibility with existing protocols, and
  52  * because it's a trivial veneer over the base DES code which is used by the
  53  * @des3@ interface which implements proper strong triple-DES.
  54  */
  55
  56 #ifndef CATACOMB_DES_H
  57 #define CATACOMB_DES_H
  58
  59 #ifdef __cplusplus
  60   extern "C" {
  61 #endif
  62
  63 /*----- Header files ------------------------------------------------------*/
  64
  65 #include <stddef.h>
  66
  67 #include <mLib/bits.h>
  68
  69 /*----- Magical numbers ---------------------------------------------------*/
  70
  71 #define DES_BLKSZ 8
  72 #define DES_KEYSZ 7
  73 #define DES_CLASS (N, B, 64)
  74
  75 extern const octet des_keysz[];
  76
  77 /*----- Data structures ---------------------------------------------------*/
  78
  79 typedef struct des_ctx {
  80   uint32 k[32];
  81 } des_ctx;
  82
  83 /*----- Functions provided ------------------------------------------------*/
  84
  85 /* --- @des_init@ --- *
  86  *
  87  * Arguments:   @des_ctx *k@ = pointer to key block
  88  *              @const void *buf@ = pointer to key buffer
  89  *              @size_t sz@ = size of key material
  90  *
  91  * Returns:     ---
  92  *
  93  * Use:         Initializes a DES key buffer.  The key buffer may be either 7
  94  *              or 8 bytes long.  If it's 8 bytes, the key is assumed to be
  95  *              padded with parity bits in the low order bit of each octet.
  96  *              These are stripped out without checking prior to the actual
  97  *              key scheduling.
  98  */
  99
 100 extern void des_init(des_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
 101
 102 /* --- @des_eblk@, @des_dblk@ --- *
 103  *
 104  * Arguments:   @const des_ctx *k@ = pointer to key block
 105  *              @const uint32 s[2]@ = pointer to source block
 106  *              @uint32 d[2]@ = pointer to destination block
 107  *
 108  * Returns:     ---
 109  *
 110  * Use:         Low-level block encryption and decryption.
 111  */
 112
 113 extern void des_eblk(const des_ctx */*k*/,
 114                      const uint32 */*s*/, uint32 */*d*/);
 115 extern void des_dblk(const des_ctx */*k*/,
 116                      const uint32 */*s*/, uint32 */*d*/);
 117
 118 /*----- That's all, folks -------------------------------------------------*/
 119
 120 #ifdef __cplusplus
 121   }
 122 #endif
 123
 124 #endif