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   1 /* -*-c-*-
   2  *
   3  * $Id: xtea.h,v 1.1 2000/07/15 13:44:31 mdw Exp $
   4  *
   5  * The 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 1.1  2000/07/15 13:44:31  mdw
  34  * New ciphers.
  35  *
  36  */
  37
  38 /*----- Notes on the Tiny Encryption Algorithm ----------------------------*
  39  *
  40  * XTEA is an amazingly simple 64-round Feistel network.  It's tiny, fairly
  41  * quick and surprisingly strong.  It was invented by David Wheeler and Roger
  42  * Needham.  It's unpatented.  XTEA is a new version of TEA, by the same
  43  * designers, which fixes some weaknesses in TEA's key schedule.
  44  *
  45  * This implementation uses big-endian byte order, following SCAN.
  46  */
  47
  48 #ifndef CATACOMB_XTEA_H
  49 #define CATACOMB_XTEA_H
  50
  51 #ifdef __cplusplus
  52   extern "C" {
  53 #endif
  54
  55 /*----- Header files ------------------------------------------------------*/
  56
  57 #include <stddef.h>
  58
  59 #include <mLib/bits.h>
  60
  61 /*----- Magical numbers ---------------------------------------------------*/
  62
  63 #define XTEA_BLKSZ 8
  64 #define XTEA_KEYSZ 16
  65 #define XTEA_CLASS (N, B, 64)
  66
  67 extern const octet xtea_keysz[];
  68
  69 /*----- Data structures ---------------------------------------------------*/
  70
  71 typedef struct xtea_ctx {
  72   uint32 k[4];
  73 } xtea_ctx;
  74
  75 /*----- Functions provided ------------------------------------------------*/
  76
  77 /* --- @xtea_init@ --- *
  78  *
  79  * Arguments:   @xtea_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 an XTEA key buffer.  The key buffer may be up to
  86  *              16 bytes long.
  87  */
  88
  89 extern void xtea_init(xtea_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
  90
  91 /* --- @xtea_eblk@, @xtea_dblk@ --- *
  92  *
  93  * Arguments:   @const xtea_ctx *k@ = pointer to key block
  94  *              @const uint32 s[2]@ = pointer to source block
  95  *              @uint32 d[2]@ = pointer to xteatination block
  96  *
  97  * Returns:     ---
  98  *
  99  * Use:         Low-level block encryption and decryption.
 100  */
 101
 102 extern void xtea_eblk(const xtea_ctx */*k*/,
 103                       const uint32 */*s*/, uint32 */*d*/);
 104 extern void xtea_dblk(const xtea_ctx */*k*/,
 105                       const uint32 */*s*/, uint32 */*d*/);
 106
 107 /*----- That's all, folks -------------------------------------------------*/
 108
 109 #ifdef __cplusplus
 110   }
 111 #endif
 112
 113 #endif