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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: idea.h,v 1.3 2000/06/17 11:24:08 mdw Exp $ |
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4 | * |
5 | * Implementation of the IDEA cipher |
6 | * |
7 | * (c) 1999 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: idea.h,v $ |
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33 | * Revision 1.3 2000/06/17 11:24:08 mdw |
34 | * New key size interface. |
35 | * |
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36 | * Revision 1.2 1999/12/10 23:29:48 mdw |
37 | * Change header file guard names. |
38 | * |
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39 | * Revision 1.1 1999/09/03 08:41:12 mdw |
40 | * Initial import. |
41 | * |
42 | */ |
43 | |
44 | /*----- Notes on the IDEA block cipher ------------------------------------* |
45 | * |
46 | * IDEA was invented by James Massey and Xuejia Lai. The fundamental idea |
47 | * underlying the cipher is combining incompatible group operations. The |
48 | * algorithm's main claim to fame is that it is the symmetric cipher in PGP |
49 | * version 2. |
50 | * |
51 | * The IDEA algorithm is allegedly patented by Ascom Tech A.G., even in the |
52 | * UK and Europe. Ascom are willing to grant licences for use in software |
53 | * which forbids commercial use, but this is not compatible with Free |
54 | * Software Foundation ideology. The author recommends against the use of |
55 | * the IDEA cipher entirely. Blowfish is conceptually simpler, appears more |
56 | * concervative, offers a larger keyspace, runs faster, and is in the public |
57 | * domain. |
58 | */ |
59 | |
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60 | #ifndef CATACOMB_IDEA_H |
61 | #define CATACOMB_IDEA_H |
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62 | |
63 | #ifdef __cplusplus |
64 | extern "C" { |
65 | #endif |
66 | |
67 | /*----- Header files ------------------------------------------------------*/ |
68 | |
69 | #include <stddef.h> |
70 | |
71 | #include <mLib/bits.h> |
72 | |
73 | /*----- Magical numbers ---------------------------------------------------*/ |
74 | |
75 | #define IDEA_BLKSZ 8 |
76 | #define IDEA_KEYSZ 16 |
77 | #define IDEA_CLASS (N, B, 64) |
78 | |
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79 | extern const octet idea_keysz[]; |
80 | |
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81 | /*----- Data structures ---------------------------------------------------*/ |
82 | |
83 | typedef struct idea_ctx { |
84 | uint16 e[52]; |
85 | uint16 d[52]; |
86 | } idea_ctx; |
87 | |
88 | /*----- Functions provided ------------------------------------------------*/ |
89 | |
90 | /* --- @idea_init@ --- * |
91 | * |
92 | * Arguments: @idea_ctx *k@ = pointer to key block |
93 | * @const void *buf@ = pointer to key buffer |
94 | * @size_t sz@ = size of key material |
95 | * |
96 | * Returns: --- |
97 | * |
98 | * Use: Initializes an IDEA key buffer. The buffer must be exactly |
99 | * 16 bytes in size, because IDEA is only defined with a key |
100 | * size of 128 bits. |
101 | */ |
102 | |
103 | extern void idea_init(idea_ctx */*k*/, const void */*buf*/, size_t /*sz*/); |
104 | |
105 | /* --- @idea_eblk@, @idea_dblk@ --- * |
106 | * |
107 | * Arguments: @const idea_ctx *k@ = pointer to a key block |
108 | * @const uint32 s[2]@ = pointer to source block |
109 | * @uint32 d[2]@ = pointer to destination block |
110 | * |
111 | * Returns: --- |
112 | * |
113 | * Use: Low-level block encryption and decryption. |
114 | */ |
115 | |
116 | extern void idea_eblk(const idea_ctx */*k*/, |
117 | const uint32 */*s*/, uint32 */*d*/); |
118 | extern void idea_dblk(const idea_ctx */*k*/, |
119 | const uint32 */*s*/, uint32 */*d*/); |
120 | |
121 | /*----- That's all, folks -------------------------------------------------*/ |
122 | |
123 | #ifdef __cplusplus |
124 | } |
125 | #endif |
126 | |
127 | #endif |