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   1 /* -*-c-*-
   2  *
   3  * $Id: serpent.h,v 1.2 2000/10/08 15:48:58 mdw Exp $
   4  *
   5  * The Serpent block cipher
   6  *
   7  * (c) 2000 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: serpent.h,v $
  33  * Revision 1.2  2000/10/08 15:48:58  mdw
  34  * Update comments now that AES has been chosen.
  35  *
  36  * Revision 1.1  2000/06/17 12:08:43  mdw
  37  * New cipher.
  38  *
  39  */
  40
  41 /*----- Notes on the Serpent block cipher ---------------------------------*
  42  *
  43  * Serpent was designed and proposed for the AES contest by Ross Anderson,
  44  * Eli Biham and Lars Knudsen.  It's not particularly quick, but is
  45  * stunningly secure.  The best differential and linear attacks are
  46  * speculated to require %$2^{256}$% texts (it's a 128-bit block cipher).
  47  * The designers originally intended to file a patent, but failed to persue
  48  * it.  Use of the algorithm is completely unencumbered.
  49  */
  50
  51 #ifndef CATACOMB_SERPENT_H
  52 #define CATACOMB_SERPENT_H
  53
  54 #ifdef __cplusplus
  55   extern "C" {
  56 #endif
  57
  58 /*----- Header files ------------------------------------------------------*/
  59
  60 #include <stddef.h>
  61
  62 #include <mLib/bits.h>
  63
  64 /*----- Magic numbers -----------------------------------------------------*/
  65
  66 #define SERPENT_BLKSZ 16
  67 #define SERPENT_KEYSZ 32
  68 #define SERPENT_CLASS (N, L, 128)
  69
  70 extern const octet serpent_keysz[];
  71
  72 /*----- Data structures ---------------------------------------------------*/
  73
  74 typedef struct serpent_ctx {
  75   uint32 k[4 * 33];
  76 } serpent_ctx;
  77
  78 /*----- Functions provided ------------------------------------------------*/
  79
  80 /* --- @serpent_init@ --- *
  81  *
  82  * Arguments:   @serpent_ctx *k@ = pointer to context block to initialize
  83  *              @const void *buf@ = pointer to input buffer
  84  *              @size_t sz@ = size of input buffer
  85  *
  86  * Returns:     ---
  87  *
  88  * Use:         Initializes a Serpent context.  The key may be any length of
  89  *              up to 32 bytes (256 bits).
  90  */
  91
  92 extern void serpent_init(serpent_ctx */*k*/,
  93                          const void */*buf*/, size_t /*sz*/);
  94
  95 /* --- @serpent_eblk@, @serpent_dblk@ --- *
  96  *
  97  * Arguments:   @const serpent_ctx *k@ = pointer to key context
  98  *              @const uint32 s[4]@ = pointer to source block
  99  *              @uint32 d[4]@ = pointer to destination block
 100  *
 101  * Returns:     ---
 102  *
 103  * Use:         Low-level block encryption.
 104  */
 105
 106 extern void serpent_eblk(const serpent_ctx */*k*/,
 107                          const uint32 */*s*/, uint32 */*d*/);
 108 extern void serpent_dblk(const serpent_ctx */*k*/,
 109                          const uint32 */*s*/, uint32 */*d*/);
 110
 111 /*----- That's all, folks -------------------------------------------------*/
 112
 113 #ifdef __cplusplus
 114   }
 115 #endif
 116
 117 #endif