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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: xtea.h,v 1.4 2004/04/08 01:36:15 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 | |
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30 | /*----- Notes on the Tiny Encryption Algorithm ----------------------------* |
31 | * |
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. |
36 | * |
37 | * This implementation uses big-endian byte order, following SCAN. |
38 | */ |
39 | |
40 | #ifndef CATACOMB_XTEA_H |
41 | #define CATACOMB_XTEA_H |
42 | |
43 | #ifdef __cplusplus |
44 | extern "C" { |
45 | #endif |
46 | |
47 | /*----- Header files ------------------------------------------------------*/ |
48 | |
49 | #include <stddef.h> |
50 | |
51 | #include <mLib/bits.h> |
52 | |
53 | /*----- Magical numbers ---------------------------------------------------*/ |
54 | |
55 | #define XTEA_BLKSZ 8 |
56 | #define XTEA_KEYSZ 16 |
57 | #define XTEA_CLASS (N, B, 64) |
58 | |
59 | extern const octet xtea_keysz[]; |
60 | |
61 | /*----- Data structures ---------------------------------------------------*/ |
62 | |
63 | typedef struct xtea_ctx { |
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64 | unsigned r; |
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65 | uint32 k[4]; |
66 | } xtea_ctx; |
67 | |
68 | /*----- Functions provided ------------------------------------------------*/ |
69 | |
70 | /* --- @xtea_init@ --- * |
71 | * |
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 |
75 | * |
76 | * Returns: --- |
77 | * |
78 | * Use: Initializes an XTEA key buffer. The key buffer may be up to |
79 | * 16 bytes long. |
80 | */ |
81 | |
82 | extern void xtea_init(xtea_ctx */*k*/, const void */*buf*/, size_t /*sz*/); |
83 | |
84 | /* --- @xtea_eblk@, @xtea_dblk@ --- * |
85 | * |
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 |
89 | * |
90 | * Returns: --- |
91 | * |
92 | * Use: Low-level block encryption and decryption. |
93 | */ |
94 | |
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*/); |
99 | |
100 | /*----- That's all, folks -------------------------------------------------*/ |
101 | |
102 | #ifdef __cplusplus |
103 | } |
104 | #endif |
105 | |
106 | #endif |