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

   1 /* -*-c-*-
   2  *
   3  * $Id: xtea.h,v 1.2 2000/07/15 13:47:14 mdw Exp $
   4  *
   5  * The Extended Tiny Encryption Algorithm
   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: xtea.h,v $
  33  * Revision 1.2  2000/07/15 13:47:14  mdw
  34  * Whoops.  Fix the purpose comment.
  35  *
  36  * Revision 1.1  2000/07/15 13:44:31  mdw
  37  * New ciphers.
  38  *
  39  */
  40
  41 /*----- Notes on the Tiny Encryption Algorithm ----------------------------*
  42  *
  43  * XTEA is an amazingly simple 64-round Feistel network.  It's tiny, fairly
  44  * quick and surprisingly strong.  It was invented by David Wheeler and Roger
  45  * Needham.  It's unpatented.  XTEA is a new version of TEA, by the same
  46  * designers, which fixes some weaknesses in TEA's key schedule.
  47  *
  48  * This implementation uses big-endian byte order, following SCAN.
  49  */
  50
  51 #ifndef CATACOMB_XTEA_H
  52 #define CATACOMB_XTEA_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 /*----- Magical numbers ---------------------------------------------------*/
  65
  66 #define XTEA_BLKSZ 8
  67 #define XTEA_KEYSZ 16
  68 #define XTEA_CLASS (N, B, 64)
  69
  70 extern const octet xtea_keysz[];
  71
  72 /*----- Data structures ---------------------------------------------------*/
  73
  74 typedef struct xtea_ctx {
  75   uint32 k[4];
  76 } xtea_ctx;
  77
  78 /*----- Functions provided ------------------------------------------------*/
  79
  80 /* --- @xtea_init@ --- *
  81  *
  82  * Arguments:   @xtea_ctx *k@ = pointer to key block
  83  *              @const void *buf@ = pointer to key buffer
  84  *              @size_t sz@ = size of key material
  85  *
  86  * Returns:     ---
  87  *
  88  * Use:         Initializes an XTEA key buffer.  The key buffer may be up to
  89  *              16 bytes long.
  90  */
  91
  92 extern void xtea_init(xtea_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
  93
  94 /* --- @xtea_eblk@, @xtea_dblk@ --- *
  95  *
  96  * Arguments:   @const xtea_ctx *k@ = pointer to key block
  97  *              @const uint32 s[2]@ = pointer to source block
  98  *              @uint32 d[2]@ = pointer to xteatination block
  99  *
 100  * Returns:     ---
 101  *
 102  * Use:         Low-level block encryption and decryption.
 103  */
 104
 105 extern void xtea_eblk(const xtea_ctx */*k*/,
 106                       const uint32 */*s*/, uint32 */*d*/);
 107 extern void xtea_dblk(const xtea_ctx */*k*/,
 108                       const uint32 */*s*/, uint32 */*d*/);
 109
 110 /*----- That's all, folks -------------------------------------------------*/
 111
 112 #ifdef __cplusplus
 113   }
 114 #endif
 115
 116 #endif