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   1 /* -*-c-*-
   2  *
   3  * $Id: square.h,v 1.2 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * The Square 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 /*----- Notes on the Square block cipher ----------------------------------*
  31  *
  32  * Invented by Joan Daemen and Vincent Rijmen, Square is a fast and
  33  * relatively simple 128-bit block cipher.  It is the predecessor to
  34  * Rijndael.  I have grave doubts about the security of Square, though: a
  35  * dedicated attack against Square's structure by Knudsen has been extended
  36  * by the Twofish team against Rijndael, and I believe that this extended
  37  * attack is also effective against Square.  This is a shame: the structure
  38  * of Square (and Rijndael) is extremely elegant, and has some extremely nice
  39  * properties.
  40  */
  41
  42 #ifndef CATACOMB_SQUARE_H
  43 #define CATACOMB_SQUARE_H
  44
  45 #ifdef __cplusplus
  46   extern "C" {
  47 #endif
  48
  49 /*----- Header files ------------------------------------------------------*/
  50
  51 #include <stddef.h>
  52
  53 #include <mLib/bits.h>
  54
  55 /*----- Magical numbers ---------------------------------------------------*/
  56
  57 #define SQUARE_BLKSZ 16
  58 #define SQUARE_KEYSZ 16
  59 #define SQUARE_CLASS (N, L, 128)
  60
  61 extern const octet square_keysz[];
  62
  63 /*----- Data structures ---------------------------------------------------*/
  64
  65 #define SQUARE_MAXROUNDS 8
  66 #define SQUARE_KWORDS ((SQUARE_MAXROUNDS + 1) * (SQUARE_BLKSZ / 4))
  67
  68 typedef struct square_ctx {
  69   uint32 w[SQUARE_KWORDS];
  70   uint32 wi[SQUARE_KWORDS];
  71 } square_ctx;
  72
  73 /*----- Functions provided ------------------------------------------------*/
  74
  75 /* --- @square_init@ --- *
  76  *
  77  * Arguments:   @square_ctx *k@ = pointer to context to initialize
  78  *              @const void *buf@ = pointer to buffer of key material
  79  *              @size_t sz@ = size of the key material
  80  *
  81  * Returns:     ---
  82  *
  83  * Use:         Initializes a Square context with a particular key.  This
  84  *              implementation of Square doesn't impose any particular
  85  *              limits on the key size except that it must be multiple of 4
  86  *              bytes long.  256 bits seems sensible, though.
  87  */
  88
  89 extern void square_init(square_ctx */*k*/,
  90                           const void */*buf*/, size_t /*sz*/);
  91
  92 /* --- @square_eblk@, @square_dblk@ --- *
  93  *
  94  * Arguments:   @const square_ctx *k@ = pointer to Square context
  95  *              @const uint32 s[4]@ = pointer to source block
  96  *              @uint32 d[4]@ = pointer to destination block
  97  *
  98  * Returns:     ---
  99  *
 100  * Use:         Low-level block encryption and decryption.
 101  */
 102
 103 extern void square_eblk(const square_ctx */*k*/,
 104                           const uint32 */*s*/, uint32 */*dst*/);
 105 extern void square_dblk(const square_ctx */*k*/,
 106                           const uint32 */*s*/, uint32 */*dst*/);
 107
 108 /*----- That's all, folks -------------------------------------------------*/
 109
 110 #ifdef __cplusplus
 111   }
 112 #endif
 113
 114 #endif