3 * $Id: xtea.h,v 1.3 2000/07/29 09:56:47 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 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 2000/07/29 09:56:47 mdw
34 * Allow the number of rounds to be configured. This isn't exported
35 * through the gcipher interface, but it may be useful anyway.
37 * Revision 1.2 2000/07/15 13:47:14 mdw
38 * Whoops. Fix the purpose comment.
40 * Revision 1.1 2000/07/15 13:44:31 mdw
45 /*----- Notes on the Tiny Encryption Algorithm ----------------------------*
47 * XTEA is an amazingly simple 64-round Feistel network. It's tiny, fairly
48 * quick and surprisingly strong. It was invented by David Wheeler and Roger
49 * Needham. It's unpatented. XTEA is a new version of TEA, by the same
50 * designers, which fixes some weaknesses in TEA's key schedule.
52 * This implementation uses big-endian byte order, following SCAN.
55 #ifndef CATACOMB_XTEA_H
56 #define CATACOMB_XTEA_H
62 /*----- Header files ------------------------------------------------------*/
66 #include <mLib/bits.h>
68 /*----- Magical numbers ---------------------------------------------------*/
72 #define XTEA_CLASS (N, B, 64)
74 extern const octet xtea_keysz
[];
76 /*----- Data structures ---------------------------------------------------*/
78 typedef struct xtea_ctx
{
83 /*----- Functions provided ------------------------------------------------*/
85 /* --- @xtea_init@ --- *
87 * Arguments: @xtea_ctx *k@ = pointer to key block
88 * @const void *buf@ = pointer to key buffer
89 * @size_t sz@ = size of key material
93 * Use: Initializes an XTEA key buffer. The key buffer may be up to
97 extern void xtea_init(xtea_ctx */
*k*/
, const void */
*buf*/
, size_t /*sz*/);
99 /* --- @xtea_eblk@, @xtea_dblk@ --- *
101 * Arguments: @const xtea_ctx *k@ = pointer to key block
102 * @const uint32 s[2]@ = pointer to source block
103 * @uint32 d[2]@ = pointer to xteatination block
107 * Use: Low-level block encryption and decryption.
110 extern void xtea_eblk(const xtea_ctx */
*k*/
,
111 const uint32 */
*s*/
, uint32 */
*d*/
);
112 extern void xtea_dblk(const xtea_ctx */
*k*/
,
113 const uint32 */
*s*/
, uint32 */
*d*/
);
115 /*----- That's all, folks -------------------------------------------------*/