Commit | Line | Data |
---|---|---|
6a0a5bdc | 1 | /* -*-c-*- |
6a0a5bdc | 2 | * |
3 | * The Skipjack block cipher | |
4 | * | |
5 | * (c) 2000 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
6a0a5bdc | 9 | * |
10 | * This file is part of Catacomb. | |
11 | * | |
12 | * Catacomb is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
45c0fd36 | 16 | * |
6a0a5bdc | 17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU Library General Public License for more details. | |
45c0fd36 | 21 | * |
6a0a5bdc | 22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
6a0a5bdc | 28 | /*----- Notes on the Skipjack block cipher --------------------------------* |
29 | * | |
30 | * Skipjack was designed by the NSA, as a type II algorithm to be used in the | |
31 | * Clipper system. It was initially classified, so that it couldn't be used | |
32 | * without the key escrow feature, though a team of `respectable' | |
33 | * cryptographers, including Dorothy Denning, had a quick look at it and | |
34 | * pronounced it `good', as if this was meant to be convincing. It is | |
35 | * apparently a particular parameterization of a family which includes type I | |
36 | * algorithms. Since declassification, Biham has discovered a miss-in-the- | |
37 | * middle attack which breaks Skipjack with 31 rounds faster than brute | |
38 | * force. | |
39 | * | |
40 | * This implementation is provided for interest's sake, and possibly for | |
41 | * interoperability, rather than as a good cipher to use. | |
42 | */ | |
43 | ||
44 | #ifndef CATACOMB_SKIPJACK_H | |
45 | #define CATACOMB_SKIPJACK_H | |
46 | ||
47 | #ifdef __cplusplus | |
48 | extern "C" { | |
49 | #endif | |
50 | ||
51 | /*----- Header files ------------------------------------------------------*/ | |
52 | ||
53 | #include <stddef.h> | |
54 | ||
55 | #include <mLib/bits.h> | |
56 | ||
57 | /*----- Magical numbers ---------------------------------------------------*/ | |
58 | ||
59 | #define SKIPJACK_BLKSZ 8 | |
60 | #define SKIPJACK_KEYSZ 10 | |
61 | #define SKIPJACK_CLASS (N, B, 64) | |
62 | ||
63 | extern const octet skipjack_keysz[]; | |
64 | ||
65 | /*----- Data structures ---------------------------------------------------*/ | |
66 | ||
67 | typedef struct skipjack_ctx { | |
fe371977 | 68 | uint32 ka, kb, kc, kd, ke; |
6a0a5bdc | 69 | } skipjack_ctx; |
70 | ||
71 | /*----- Functions provided ------------------------------------------------*/ | |
72 | ||
73 | /* --- @skipjack_init@ --- * | |
74 | * | |
45c0fd36 MW |
75 | * Arguments: @skipjack_ctx *k@ = pointer to key block |
76 | * @const void *buf@ = pointer to key buffer | |
77 | * @size_t sz@ = size of key material | |
6a0a5bdc | 78 | * |
45c0fd36 | 79 | * Returns: --- |
6a0a5bdc | 80 | * |
45c0fd36 | 81 | * Use: Initializes a Skipjack key buffer. The key buffer must be |
6a0a5bdc | 82 | * exactly 10 bytes long. |
83 | */ | |
84 | ||
85 | extern void skipjack_init(skipjack_ctx */*k*/, | |
86 | const void */*buf*/, size_t /*sz*/); | |
87 | ||
88 | /* --- @skipjack_eblk@, @skipjack_dblk@ --- * | |
89 | * | |
45c0fd36 MW |
90 | * Arguments: @const skipjack_ctx *k@ = pointer to key block |
91 | * @const uint32 s[2]@ = pointer to source block | |
92 | * @uint32 d[2]@ = pointer to skipjacktination block | |
6a0a5bdc | 93 | * |
45c0fd36 | 94 | * Returns: --- |
6a0a5bdc | 95 | * |
45c0fd36 | 96 | * Use: Low-level block encryption and decryption. |
6a0a5bdc | 97 | */ |
98 | ||
99 | extern void skipjack_eblk(const skipjack_ctx */*k*/, | |
100 | const uint32 */*s*/, uint32 */*d*/); | |
101 | extern void skipjack_dblk(const skipjack_ctx */*k*/, | |
102 | const uint32 */*s*/, uint32 */*d*/); | |
103 | ||
104 | /*----- That's all, folks -------------------------------------------------*/ | |
105 | ||
106 | #ifdef __cplusplus | |
107 | } | |
108 | #endif | |
109 | ||
110 | #endif |