3 * $Id: xtea.h,v 1.4 2004/04/08 01:36:15 mdw Exp $
5 * The Extended Tiny Encryption Algorithm
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Notes on the Tiny Encryption Algorithm ----------------------------*
32 * XTEA is an amazingly simple 64-round Feistel network. It's tiny, fairly
33 * quick and surprisingly strong. It was invented by David Wheeler and Roger
34 * Needham. It's unpatented. XTEA is a new version of TEA, by the same
35 * designers, which fixes some weaknesses in TEA's key schedule.
37 * This implementation uses big-endian byte order, following SCAN.
40 #ifndef CATACOMB_XTEA_H
41 #define CATACOMB_XTEA_H
47 /*----- Header files ------------------------------------------------------*/
51 #include <mLib/bits.h>
53 /*----- Magical numbers ---------------------------------------------------*/
57 #define XTEA_CLASS (N, B, 64)
59 extern const octet xtea_keysz
[];
61 /*----- Data structures ---------------------------------------------------*/
63 typedef struct xtea_ctx
{
68 /*----- Functions provided ------------------------------------------------*/
70 /* --- @xtea_init@ --- *
72 * Arguments: @xtea_ctx *k@ = pointer to key block
73 * @const void *buf@ = pointer to key buffer
74 * @size_t sz@ = size of key material
78 * Use: Initializes an XTEA key buffer. The key buffer may be up to
82 extern void xtea_init(xtea_ctx */
*k*/
, const void */
*buf*/
, size_t /*sz*/);
84 /* --- @xtea_eblk@, @xtea_dblk@ --- *
86 * Arguments: @const xtea_ctx *k@ = pointer to key block
87 * @const uint32 s[2]@ = pointer to source block
88 * @uint32 d[2]@ = pointer to xteatination block
92 * Use: Low-level block encryption and decryption.
95 extern void xtea_eblk(const xtea_ctx */
*k*/
,
96 const uint32 */
*s*/
, uint32 */
*d*/
);
97 extern void xtea_dblk(const xtea_ctx */
*k*/
,
98 const uint32 */
*s*/
, uint32 */
*d*/
);
100 /*----- That's all, folks -------------------------------------------------*/