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1 | /* -*-c-*- |
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2 | * |
3 | * The DESX algorithm |
4 | * |
5 | * (c) 2001 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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16 | * |
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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. |
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21 | * |
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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 | |
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28 | /*----- Notes on DESX -----------------------------------------------------* |
29 | * |
30 | * DESX was designed by Ron Rivest in 1986 as a simple and cheap way to |
31 | * strengthen DES against exhaustive search. It also increases the |
32 | * difficulty of differential and linear attacks. |
33 | */ |
34 | |
35 | #ifndef CATACOMB_DESX_H |
36 | #define CATACOMB_DESX_H |
37 | |
38 | #ifdef __cplusplus |
39 | extern "C" { |
40 | #endif |
41 | |
42 | /*----- Header files ------------------------------------------------------*/ |
43 | |
44 | #include <stddef.h> |
45 | |
46 | #include <mLib/bits.h> |
47 | |
48 | #ifndef CATACOMB_DES_H |
49 | # include "des.h" |
50 | #endif |
51 | |
52 | /*----- Magical numbers ---------------------------------------------------*/ |
53 | |
54 | #define DESX_BLKSZ 8 |
55 | #define DESX_KEYSZ 23 |
56 | #define DESX_CLASS (N, B, 64) |
57 | |
58 | extern const octet desx_keysz[]; |
59 | |
60 | /*----- Data structures ---------------------------------------------------*/ |
61 | |
62 | typedef struct desx_ctx { |
63 | des_ctx k; |
64 | uint32 prea, preb; |
65 | uint32 posta, postb; |
66 | } desx_ctx; |
67 | |
68 | /*----- Functions provided ------------------------------------------------*/ |
69 | |
70 | /* --- @desx_init@ --- * |
71 | * |
72 | * Arguments: @desx_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 a DESX key buffer. The key buffer contains, in |
79 | * order, an optional 8-byte pre-whitening key, a single-DES key |
80 | * (either 7 or 8 bytes), and an optional 8-byte port-whitening |
81 | * key. If no whitening keys are specified, the algorithm |
82 | * becomes the same as single-DES. |
83 | */ |
84 | |
85 | extern void desx_init(desx_ctx */*k*/, const void */*buf*/, size_t /*sz*/); |
86 | |
87 | /* --- @desx_eblk@, @desx_dblk@ --- * |
88 | * |
89 | * Arguments: @const desx_ctx *k@ = pointer to key block |
90 | * @const uint32 s[2]@ = pointer to source block |
91 | * @uint32 d[2]@ = pointer to destination block |
92 | * |
93 | * Returns: --- |
94 | * |
95 | * Use: Low-level block encryption and decryption. |
96 | */ |
97 | |
98 | extern void desx_eblk(const desx_ctx */*k*/, |
99 | const uint32 */*s*/, uint32 */*d*/); |
100 | extern void desx_dblk(const desx_ctx */*k*/, |
101 | const uint32 */*s*/, uint32 */*d*/); |
102 | |
103 | /*----- That's all, folks -------------------------------------------------*/ |
104 | |
105 | #ifdef __cplusplus |
106 | } |
107 | #endif |
108 | |
109 | #endif |