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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: xtea.h,v 1.2 2000/07/15 13:47:14 mdw Exp $ |
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4 | * |
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5 | * The Extended Tiny Encryption Algorithm |
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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 $ |
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33 | * Revision 1.2 2000/07/15 13:47:14 mdw |
34 | * Whoops. Fix the purpose comment. |
35 | * |
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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 |