3 * $Id: tea.h,v 1.3 2004/04/08 01:36:15 mdw Exp $
5 * The 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 * TEA 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. The keyspace is has only 126 effective bits,
35 * and there are related-key attacks. If you want these fixed, use XTEA.
37 * This implementation uses big-endian byte order, following SCAN.
40 #ifndef CATACOMB_TEA_H
41 #define CATACOMB_TEA_H
47 /*----- Header files ------------------------------------------------------*/
51 #include <mLib/bits.h>
53 /*----- Magical numbers ---------------------------------------------------*/
57 #define TEA_CLASS (N, B, 64)
59 extern const octet tea_keysz
[];
61 /*----- Data structures ---------------------------------------------------*/
63 typedef struct tea_ctx
{
65 uint32 ka
, kb
, kc
, kd
;
68 /*----- Functions provided ------------------------------------------------*/
70 /* --- @tea_init@ --- *
72 * Arguments: @tea_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 a TEA key buffer. The key buffer may be up to 16
82 extern void tea_init(tea_ctx */
*k*/
, const void */
*buf*/
, size_t /*sz*/);
84 /* --- @tea_eblk@, @tea_dblk@ --- *
86 * Arguments: @const tea_ctx *k@ = pointer to key block
87 * @const uint32 s[2]@ = pointer to source block
88 * @uint32 d[2]@ = pointer to teatination block
92 * Use: Low-level block encryption and decryption.
95 extern void tea_eblk(const tea_ctx */
*k*/
,
96 const uint32 */
*s*/
, uint32 */
*d*/
);
97 extern void tea_dblk(const tea_ctx */
*k*/
,
98 const uint32 */
*s*/
, uint32 */
*d*/
);
100 /*----- That's all, folks -------------------------------------------------*/