Commit | Line | Data |
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6a0a5bdc | 1 | /* -*-c-*- |
2 | * | |
b817bfc6 | 3 | * $Id: skipjack.h,v 1.3 2004/04/08 01:36:15 mdw Exp $ |
6a0a5bdc | 4 | * |
5 | * The Skipjack block cipher | |
6 | * | |
7 | * (c) 2000 Straylight/Edgeware | |
8 | */ | |
9 | ||
45c0fd36 | 10 | /*----- Licensing notice --------------------------------------------------* |
6a0a5bdc | 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. | |
45c0fd36 | 18 | * |
6a0a5bdc | 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. | |
45c0fd36 | 23 | * |
6a0a5bdc | 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 | ||
6a0a5bdc | 30 | /*----- Notes on the Skipjack block cipher --------------------------------* |
31 | * | |
32 | * Skipjack was designed by the NSA, as a type II algorithm to be used in the | |
33 | * Clipper system. It was initially classified, so that it couldn't be used | |
34 | * without the key escrow feature, though a team of `respectable' | |
35 | * cryptographers, including Dorothy Denning, had a quick look at it and | |
36 | * pronounced it `good', as if this was meant to be convincing. It is | |
37 | * apparently a particular parameterization of a family which includes type I | |
38 | * algorithms. Since declassification, Biham has discovered a miss-in-the- | |
39 | * middle attack which breaks Skipjack with 31 rounds faster than brute | |
40 | * force. | |
41 | * | |
42 | * This implementation is provided for interest's sake, and possibly for | |
43 | * interoperability, rather than as a good cipher to use. | |
44 | */ | |
45 | ||
46 | #ifndef CATACOMB_SKIPJACK_H | |
47 | #define CATACOMB_SKIPJACK_H | |
48 | ||
49 | #ifdef __cplusplus | |
50 | extern "C" { | |
51 | #endif | |
52 | ||
53 | /*----- Header files ------------------------------------------------------*/ | |
54 | ||
55 | #include <stddef.h> | |
56 | ||
57 | #include <mLib/bits.h> | |
58 | ||
59 | /*----- Magical numbers ---------------------------------------------------*/ | |
60 | ||
61 | #define SKIPJACK_BLKSZ 8 | |
62 | #define SKIPJACK_KEYSZ 10 | |
63 | #define SKIPJACK_CLASS (N, B, 64) | |
64 | ||
65 | extern const octet skipjack_keysz[]; | |
66 | ||
67 | /*----- Data structures ---------------------------------------------------*/ | |
68 | ||
69 | typedef struct skipjack_ctx { | |
fe371977 | 70 | uint32 ka, kb, kc, kd, ke; |
6a0a5bdc | 71 | } skipjack_ctx; |
72 | ||
73 | /*----- Functions provided ------------------------------------------------*/ | |
74 | ||
75 | /* --- @skipjack_init@ --- * | |
76 | * | |
45c0fd36 MW |
77 | * Arguments: @skipjack_ctx *k@ = pointer to key block |
78 | * @const void *buf@ = pointer to key buffer | |
79 | * @size_t sz@ = size of key material | |
6a0a5bdc | 80 | * |
45c0fd36 | 81 | * Returns: --- |
6a0a5bdc | 82 | * |
45c0fd36 | 83 | * Use: Initializes a Skipjack key buffer. The key buffer must be |
6a0a5bdc | 84 | * exactly 10 bytes long. |
85 | */ | |
86 | ||
87 | extern void skipjack_init(skipjack_ctx */*k*/, | |
88 | const void */*buf*/, size_t /*sz*/); | |
89 | ||
90 | /* --- @skipjack_eblk@, @skipjack_dblk@ --- * | |
91 | * | |
45c0fd36 MW |
92 | * Arguments: @const skipjack_ctx *k@ = pointer to key block |
93 | * @const uint32 s[2]@ = pointer to source block | |
94 | * @uint32 d[2]@ = pointer to skipjacktination block | |
6a0a5bdc | 95 | * |
45c0fd36 | 96 | * Returns: --- |
6a0a5bdc | 97 | * |
45c0fd36 | 98 | * Use: Low-level block encryption and decryption. |
6a0a5bdc | 99 | */ |
100 | ||
101 | extern void skipjack_eblk(const skipjack_ctx */*k*/, | |
102 | const uint32 */*s*/, uint32 */*d*/); | |
103 | extern void skipjack_dblk(const skipjack_ctx */*k*/, | |
104 | const uint32 */*s*/, uint32 */*d*/); | |
105 | ||
106 | /*----- That's all, folks -------------------------------------------------*/ | |
107 | ||
108 | #ifdef __cplusplus | |
109 | } | |
110 | #endif | |
111 | ||
112 | #endif |