| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * The CAST-128 block cipher |
| 4 | * |
| 5 | * (c) 2000 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 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. |
| 16 | * |
| 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. |
| 21 | * |
| 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 | |
| 28 | /*----- Notes on the CAST-256 block cipher --------------------------------* |
| 29 | * |
| 30 | * CAST, designed by Carlisle Adams and Stafford Tavares, is a method for |
| 31 | * designing block ciphers, based around the concept of `bent functions'. It |
| 32 | * is described in the paper `Constructing Symmetric Ciphers using the CAST |
| 33 | * Design Procedure' by Carlisle Adams. |
| 34 | * |
| 35 | * CAST-256, defined in RFC2612, is a particular instance of the CAST design |
| 36 | * procedure. It is an `incomplete' Feistel network. It uses the same |
| 37 | * S-boxes and round functions as CAST-128. |
| 38 | * |
| 39 | * CAST-256 was submitted to the AES contest, but was not selected as one of |
| 40 | * the five `finalist' algorithms. |
| 41 | */ |
| 42 | |
| 43 | #ifndef CATACOMB_CAST256_H |
| 44 | #define CATACOMB_CAST256_H |
| 45 | |
| 46 | #ifdef __cplusplus |
| 47 | extern "C" { |
| 48 | #endif |
| 49 | |
| 50 | /*----- Header files ------------------------------------------------------*/ |
| 51 | |
| 52 | #include <mLib/bits.h> |
| 53 | |
| 54 | /*----- Magic numbers -----------------------------------------------------*/ |
| 55 | |
| 56 | #define CAST256_BLKSZ 16 |
| 57 | #define CAST256_KEYSZ 32 |
| 58 | #define CAST256_CLASS (N, B, 128) |
| 59 | |
| 60 | extern const octet cast256_keysz[]; |
| 61 | |
| 62 | /*----- Data structures ---------------------------------------------------*/ |
| 63 | |
| 64 | typedef struct cast256_ctx { |
| 65 | uint32 km[48]; |
| 66 | octet kr[48]; |
| 67 | } cast256_ctx; |
| 68 | |
| 69 | /*----- Functions provided ------------------------------------------------*/ |
| 70 | |
| 71 | /* --- @cast256_init@ --- * |
| 72 | * |
| 73 | * Arguments: @cast256_ctx *k@ = pointer to key block to fill in |
| 74 | * @const void *buf@ = pointer to buffer of key material |
| 75 | * @size_t sz@ = size of key material |
| 76 | * |
| 77 | * Returns: --- |
| 78 | * |
| 79 | * Use: Initializes a CAST-256 key buffer. CAST-256 accepts |
| 80 | * 256-bit keys or shorter. |
| 81 | */ |
| 82 | |
| 83 | extern void cast256_init(cast256_ctx */*k*/, |
| 84 | const void */*buf*/, size_t /*sz*/); |
| 85 | |
| 86 | /* --- @cast256_eblk@, @cast256_dblk@ --- * |
| 87 | * |
| 88 | * Arguments: @const cast256_ctx *k@ = pointer to key block |
| 89 | * @const uint32 s[2]@ = pointer to source block |
| 90 | * @uint32 d[2]@ = pointer to destination block |
| 91 | * |
| 92 | * Returns: --- |
| 93 | * |
| 94 | * Use: Low-level block encryption and decryption. |
| 95 | */ |
| 96 | |
| 97 | extern void cast256_eblk(const cast256_ctx */*k*/, |
| 98 | const uint32 */*s*/, uint32 */*d*/); |
| 99 | |
| 100 | extern void cast256_dblk(const cast256_ctx */*k*/, |
| 101 | const uint32 */*s*/, uint32 */*d*/); |
| 102 | |
| 103 | /*----- That's all, folks -------------------------------------------------*/ |
| 104 | |
| 105 | #ifdef __cplusplus |
| 106 | } |
| 107 | #endif |
| 108 | |
| 109 | #endif |