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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: tea.h,v 1.2 2000/07/29 09:56:47 mdw Exp $ |
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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: tea.h,v $ |
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33 | * Revision 1.2 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. |
36 | * |
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37 | * Revision 1.1 2000/07/15 13:44:31 mdw |
38 | * New ciphers. |
39 | * |
40 | */ |
41 | |
42 | /*----- Notes on the Tiny Encryption Algorithm ----------------------------* |
43 | * |
44 | * TEA is an amazingly simple 64-round Feistel network. It's tiny, fairly |
45 | * quick and surprisingly strong. It was invented by David Wheeler and Roger |
46 | * Needham. It's unpatented. The keyspace is has only 126 effective bits, |
47 | * and there are related-key attacks. If you want these fixed, use XTEA. |
48 | * |
49 | * This implementation uses big-endian byte order, following SCAN. |
50 | */ |
51 | |
52 | #ifndef CATACOMB_TEA_H |
53 | #define CATACOMB_TEA_H |
54 | |
55 | #ifdef __cplusplus |
56 | extern "C" { |
57 | #endif |
58 | |
59 | /*----- Header files ------------------------------------------------------*/ |
60 | |
61 | #include <stddef.h> |
62 | |
63 | #include <mLib/bits.h> |
64 | |
65 | /*----- Magical numbers ---------------------------------------------------*/ |
66 | |
67 | #define TEA_BLKSZ 8 |
68 | #define TEA_KEYSZ 16 |
69 | #define TEA_CLASS (N, B, 64) |
70 | |
71 | extern const octet tea_keysz[]; |
72 | |
73 | /*----- Data structures ---------------------------------------------------*/ |
74 | |
75 | typedef struct tea_ctx { |
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76 | unsigned r; |
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77 | uint32 ka, kb, kc, kd; |
78 | } tea_ctx; |
79 | |
80 | /*----- Functions provided ------------------------------------------------*/ |
81 | |
82 | /* --- @tea_init@ --- * |
83 | * |
84 | * Arguments: @tea_ctx *k@ = pointer to key block |
85 | * @const void *buf@ = pointer to key buffer |
86 | * @size_t sz@ = size of key material |
87 | * |
88 | * Returns: --- |
89 | * |
90 | * Use: Initializes a TEA key buffer. The key buffer may be up to 16 |
91 | * bytes long. |
92 | */ |
93 | |
94 | extern void tea_init(tea_ctx */*k*/, const void */*buf*/, size_t /*sz*/); |
95 | |
96 | /* --- @tea_eblk@, @tea_dblk@ --- * |
97 | * |
98 | * Arguments: @const tea_ctx *k@ = pointer to key block |
99 | * @const uint32 s[2]@ = pointer to source block |
100 | * @uint32 d[2]@ = pointer to teatination block |
101 | * |
102 | * Returns: --- |
103 | * |
104 | * Use: Low-level block encryption and decryption. |
105 | */ |
106 | |
107 | extern void tea_eblk(const tea_ctx */*k*/, |
108 | const uint32 */*s*/, uint32 */*d*/); |
109 | extern void tea_dblk(const tea_ctx */*k*/, |
110 | const uint32 */*s*/, uint32 */*d*/); |
111 | |
112 | /*----- That's all, folks -------------------------------------------------*/ |
113 | |
114 | #ifdef __cplusplus |
115 | } |
116 | #endif |
117 | |
118 | #endif |