git.distorted.org.uk Git - u/mdw/catacomb/blob - des.h

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