3a65506d |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: rc2.h,v 1.1 2000/06/17 11:54:34 mdw Exp $ |
4 | * |
5 | * The RC2 block cipher |
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 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: rc2.h,v $ |
33 | * Revision 1.1 2000/06/17 11:54:34 mdw |
34 | * New cipher. |
35 | * |
36 | */ |
37 | |
38 | /*----- Notes on the RC2 block cipher -------------------------------------* |
39 | * |
40 | * RC2 was designed by Ron Rivest, and for a long time was a trade secret of |
41 | * RSA Data Security Inc. Like RC4, it leaked out, and has now been |
42 | * described in RFC2268. The RC2 key schedule is known to have some |
43 | * weaknesses, although I'm not aware of any major results against the cipher |
44 | * itself. I'm also not aware of any legal problems with using the RC2 |
45 | * cipher. |
46 | * |
47 | * The oddest feature in the cipher is the key schedule. It expands the |
48 | * initial key material to 128 bytes, and then `brain-damages' it, according |
49 | * to a supplied `effective key-bits' parameter, before expanding the |
50 | * remaining key material back into the buffer. |
51 | * |
52 | * The key schedule allows second preimages to be computed trivially. |
53 | */ |
54 | |
55 | #ifndef CATACOMB_RC2_H |
56 | #define CATACOMB_RC2_H |
57 | |
58 | #ifdef __cplusplus |
59 | extern "C" { |
60 | #endif |
61 | |
62 | /*----- Header files ------------------------------------------------------*/ |
63 | |
64 | #include <stddef.h> |
65 | |
66 | #include <mLib/bits.h> |
67 | |
68 | /*----- Magical numbers ---------------------------------------------------*/ |
69 | |
70 | #define RC2_BLKSZ 8 |
71 | #define RC2_KEYSZ 16 |
72 | #define RC2_CLASS (N, L, 64) |
73 | |
74 | extern const octet rc2_keysz[]; |
75 | |
76 | /*----- Data structures ---------------------------------------------------*/ |
77 | |
78 | typedef struct rc2_ctx { |
79 | uint16 k[64]; |
80 | } rc2_ctx; |
81 | |
82 | /*----- Functions provided ------------------------------------------------*/ |
83 | |
84 | /* --- @rc2_braindamage@ --- * |
85 | * |
86 | * Arguments: @rc2_ctx *k@ = pointer to context to initialize |
87 | * @const void *buf@ = pointer to key material |
88 | * @size_t sz@ = size of key material in bytes |
89 | * @unsigned eb@ = desired effective key size, in bits |
90 | * |
91 | * Returns: --- |
92 | * |
93 | * Use: Initializes an RC2 expanded key, and braindamages it to the |
94 | * requested effective key size. This is here for compatibility |
95 | * reasons. You should be using @rc2_init@ in normal code, |
96 | * which doesn't actually apply braindamage. |
97 | */ |
98 | |
99 | extern void rc2_braindamage(rc2_ctx */*k*/, const void */*buf*/, |
100 | size_t /*sz*/, unsigned /*eb*/); |
101 | |
102 | /* --- @rc2_init@ --- * |
103 | * |
104 | * Arguments: @rc2_ctx *k@ = pointer to context to initialize |
105 | * @const void *buf@ = pointer to key material |
106 | * @size_t sz@ = size of key material in bytes |
107 | * |
108 | * Returns: --- |
109 | * |
110 | * Use: Initializes an RC2 expanded key. The effective key size is |
111 | * set to be equal to the real key size, in bits. |
112 | */ |
113 | |
114 | extern void rc2_init(rc2_ctx */*k*/, const void */*buf*/, size_t /*sz*/); |
115 | |
116 | /* --- @rc2_eblk@, @rc2_dblk@ --- * |
117 | * |
118 | * Arguments: @const rc2_ctx *k@ = pointer to RC2 context |
119 | * @const uint32 s[2]@ = pointer to source block |
120 | * @const uint32 d[2]@ = pointer to destination block |
121 | * |
122 | * Returns: --- |
123 | * |
124 | * Use: Low-level block encryption and decryption. |
125 | */ |
126 | |
127 | extern void rc2_eblk(const rc2_ctx */*k*/, |
128 | const uint32 */*s*/, uint32 */*dst*/); |
129 | extern void rc2_dblk(const rc2_ctx */*k*/, |
130 | const uint32 */*s*/, uint32 */*dst*/); |
131 | |
132 | /*----- That's all, folks -------------------------------------------------*/ |
133 | |
134 | #ifdef __cplusplus |
135 | } |
136 | #endif |
137 | |
138 | #endif |