9810d749 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: cast128.h,v 1.1 2000/06/17 10:49:14 mdw Exp $ |
4 | * |
5 | * The CAST-128 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: cast128.h,v $ |
33 | * Revision 1.1 2000/06/17 10:49:14 mdw |
34 | * New cipher. |
35 | * |
36 | */ |
37 | |
38 | /*----- Notes on the CAST-128 block cipher --------------------------------* |
39 | * |
40 | * CAST, designed by Carlisle Adams and Stafford Tavares, is a method for |
41 | * designing block ciphers, based around the concept of `bent functions'. It |
42 | * is described in the paper `Constructing Symmetric Ciphers using the CAST |
43 | * Design Procedure' by Carlisle Adams. |
44 | * |
45 | * CAST-128, defined in RFC2144, is a particular instance of the CAST design |
46 | * procedure, The cipher seems strong and fairly quick. The design procedure |
47 | * itself is patented, although the cipher CAST-128 is free to use. |
48 | * |
49 | * Although CAST ciphers are resistant to differential and linear |
50 | * cryptanalysis, some instances have been broken by more advanced techniques |
51 | * -- the CAST procedure does not guarantee a strong cipher. However, |
52 | * CAST-128 has so far resisted all attacks against it, and has now been |
53 | * accepted by the Canadian government for protection of all `Designated' |
54 | * material. |
55 | */ |
56 | |
57 | #ifndef CATACOMB_CAST128_H |
58 | #define CATACOMB_CAST128_H |
59 | |
60 | #ifdef __cplusplus |
61 | extern "C" { |
62 | #endif |
63 | |
64 | /*----- Header files ------------------------------------------------------*/ |
65 | |
66 | #include <mLib/bits.h> |
67 | |
68 | /*----- Magic numbers -----------------------------------------------------*/ |
69 | |
70 | #define CAST128_BLKSZ 8 |
71 | #define CAST128_KEYSZ 16 |
72 | #define CAST128_CLASS (N, B, 64) |
73 | |
74 | extern const octet cast128_keysz[]; |
75 | |
76 | /*----- Data structures ---------------------------------------------------*/ |
77 | |
78 | typedef struct cast128_ctx { |
79 | unsigned r; |
80 | uint32 km[16]; |
81 | octet kr[16]; |
82 | } cast128_ctx; |
83 | |
84 | /*----- Functions provided ------------------------------------------------*/ |
85 | |
86 | /* --- @cast128_init@ --- * |
87 | * |
88 | * Arguments: @cast128_ctx *k@ = pointer to key block to fill in |
89 | * @const void *buf@ = pointer to buffer of key material |
90 | * @size_t sz@ = size of key material |
91 | * |
92 | * Returns: --- |
93 | * |
94 | * Use: Initializes a CAST-128 key buffer. CAST-128 accepts |
95 | * 128-bit keys or shorter. |
96 | */ |
97 | |
98 | extern void cast128_init(cast128_ctx */*k*/, |
99 | const void */*buf*/, size_t /*sz*/); |
100 | |
101 | /* --- @cast128_eblk@, @cast128_dblk@ --- * |
102 | * |
103 | * Arguments: @const cast128_ctx *k@ = pointer to key block |
104 | * @const uint32 s[2]@ = pointer to source block |
105 | * @uint32 d[2]@ = pointer to destination block |
106 | * |
107 | * Returns: --- |
108 | * |
109 | * Use: Low-level block encryption and decryption. |
110 | */ |
111 | |
112 | extern void cast128_eblk(const cast128_ctx */*k*/, |
113 | const uint32 */*s*/, uint32 */*d*/); |
114 | |
115 | extern void cast128_dblk(const cast128_ctx */*k*/, |
116 | const uint32 */*s*/, uint32 */*d*/); |
117 | |
118 | /*----- That's all, folks -------------------------------------------------*/ |
119 | |
120 | #ifdef __cplusplus |
121 | } |
122 | #endif |
123 | |
124 | #endif |