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

   1 /* -*-c-*-
   2  *
   3  * The Serpent block cipher
   4  *
   5  * (c) 2000 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Notes on the Serpent block cipher ---------------------------------*
  29  *
  30  * Serpent was designed and proposed for the AES contest by Ross Anderson,
  31  * Eli Biham and Lars Knudsen.  It's not particularly quick, but is
  32  * stunningly secure.  The best differential and linear attacks are
  33  * speculated to require %$2^{256}$% texts (it's a 128-bit block cipher).
  34  * The designers originally intended to file a patent, but failed to persue
  35  * it.  Use of the algorithm is completely unencumbered.
  36  */
  37
  38 #ifndef CATACOMB_SERPENT_H
  39 #define CATACOMB_SERPENT_H
  40
  41 #ifdef __cplusplus
  42   extern "C" {
  43 #endif
  44
  45 /*----- Header files ------------------------------------------------------*/
  46
  47 #include <stddef.h>
  48
  49 #include <mLib/bits.h>
  50
  51 /*----- Magic numbers -----------------------------------------------------*/
  52
  53 #define SERPENT_BLKSZ 16
  54 #define SERPENT_KEYSZ 32
  55 #define SERPENT_CLASS (N, L, 128)
  56
  57 extern const octet serpent_keysz[];
  58
  59 /*----- Data structures ---------------------------------------------------*/
  60
  61 typedef struct serpent_ctx {
  62   uint32 k[4 * 33];
  63 } serpent_ctx;
  64
  65 /*----- Functions provided ------------------------------------------------*/
  66
  67 /* --- @serpent_init@ --- *
  68  *
  69  * Arguments:   @serpent_ctx *k@ = pointer to context block to initialize
  70  *              @const void *buf@ = pointer to input buffer
  71  *              @size_t sz@ = size of input buffer
  72  *
  73  * Returns:     ---
  74  *
  75  * Use:         Initializes a Serpent context.  The key may be any length of
  76  *              up to 32 bytes (256 bits).
  77  */
  78
  79 extern void serpent_init(serpent_ctx */*k*/,
  80                          const void */*buf*/, size_t /*sz*/);
  81
  82 /* --- @serpent_eblk@, @serpent_dblk@ --- *
  83  *
  84  * Arguments:   @const serpent_ctx *k@ = pointer to key context
  85  *              @const uint32 s[4]@ = pointer to source block
  86  *              @uint32 d[4]@ = pointer to destination block
  87  *
  88  * Returns:     ---
  89  *
  90  * Use:         Low-level block encryption.
  91  */
  92
  93 extern void serpent_eblk(const serpent_ctx */*k*/,
  94                          const uint32 */*s*/, uint32 */*d*/);
  95 extern void serpent_dblk(const serpent_ctx */*k*/,
  96                          const uint32 */*s*/, uint32 */*d*/);
  97
  98 /*----- That's all, folks -------------------------------------------------*/
  99
 100 #ifdef __cplusplus
 101   }
 102 #endif
 103
 104 #endif