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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: cast256.h,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The CAST-128 block cipher |
6 | * |
7 | * (c) 2000 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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18 | * |
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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. |
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23 | * |
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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 | |
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30 | /*----- Notes on the CAST-256 block cipher --------------------------------* |
31 | * |
32 | * CAST, designed by Carlisle Adams and Stafford Tavares, is a method for |
33 | * designing block ciphers, based around the concept of `bent functions'. It |
34 | * is described in the paper `Constructing Symmetric Ciphers using the CAST |
35 | * Design Procedure' by Carlisle Adams. |
36 | * |
37 | * CAST-256, defined in RFC2612, is a particular instance of the CAST design |
38 | * procedure. It is an `incomplete' Feistel network. It uses the same |
39 | * S-boxes and round functions as CAST-128. |
40 | * |
41 | * CAST-256 was submitted to the AES contest, but was not selected as one of |
42 | * the five `finalist' algorithms. |
43 | */ |
44 | |
45 | #ifndef CATACOMB_CAST256_H |
46 | #define CATACOMB_CAST256_H |
47 | |
48 | #ifdef __cplusplus |
49 | extern "C" { |
50 | #endif |
51 | |
52 | /*----- Header files ------------------------------------------------------*/ |
53 | |
54 | #include <mLib/bits.h> |
55 | |
56 | /*----- Magic numbers -----------------------------------------------------*/ |
57 | |
58 | #define CAST256_BLKSZ 16 |
59 | #define CAST256_KEYSZ 32 |
60 | #define CAST256_CLASS (N, B, 128) |
61 | |
62 | extern const octet cast256_keysz[]; |
63 | |
64 | /*----- Data structures ---------------------------------------------------*/ |
65 | |
66 | typedef struct cast256_ctx { |
67 | uint32 km[48]; |
68 | octet kr[48]; |
69 | } cast256_ctx; |
70 | |
71 | /*----- Functions provided ------------------------------------------------*/ |
72 | |
73 | /* --- @cast256_init@ --- * |
74 | * |
75 | * Arguments: @cast256_ctx *k@ = pointer to key block to fill in |
76 | * @const void *buf@ = pointer to buffer of key material |
77 | * @size_t sz@ = size of key material |
78 | * |
79 | * Returns: --- |
80 | * |
81 | * Use: Initializes a CAST-256 key buffer. CAST-256 accepts |
82 | * 256-bit keys or shorter. |
83 | */ |
84 | |
85 | extern void cast256_init(cast256_ctx */*k*/, |
86 | const void */*buf*/, size_t /*sz*/); |
87 | |
88 | /* --- @cast256_eblk@, @cast256_dblk@ --- * |
89 | * |
90 | * Arguments: @const cast256_ctx *k@ = pointer to key block |
91 | * @const uint32 s[2]@ = pointer to source block |
92 | * @uint32 d[2]@ = pointer to destination block |
93 | * |
94 | * Returns: --- |
95 | * |
96 | * Use: Low-level block encryption and decryption. |
97 | */ |
98 | |
99 | extern void cast256_eblk(const cast256_ctx */*k*/, |
100 | const uint32 */*s*/, uint32 */*d*/); |
101 | |
102 | extern void cast256_dblk(const cast256_ctx */*k*/, |
103 | const uint32 */*s*/, uint32 */*d*/); |
104 | |
105 | /*----- That's all, folks -------------------------------------------------*/ |
106 | |
107 | #ifdef __cplusplus |
108 | } |
109 | #endif |
110 | |
111 | #endif |