git.distorted.org.uk Git - u/mdw/catacomb/blob - symm/cast256.h

   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