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

   1 /* -*-c-*-
   2  *
   3  * The SAFER block cipher
   4  *
   5  * (c) 2001 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 SAFER block cipher -----------------------------------*
  29  *
  30  * SAFER was designed by James Massey (who also worked on IDEA) for Cylink.
  31  * It's free -- patents or other silliness.  The original key schedule had
  32  * some weaknesses, and a new one (the SK version) was added.  SAFER has a
  33  * variable number of rounds.  The standard interface uses the recommended
  34  * number for the given key schedule algorithm and key size.
  35  *
  36  * SAFER got a bad press in Schneier's book `Applied Cryptography'.  I think
  37  * this is undeserved.  SAFER is a well-designed cipher which mostly looks
  38  * pretty solid.
  39  */
  40
  41 #ifndef CATACOMB_SAFER_H
  42 #define CATACOMB_SAFER_H
  43
  44 #ifdef __cplusplus
  45   extern "C" {
  46 #endif
  47
  48 /*----- Header files ------------------------------------------------------*/
  49
  50 #include <stddef.h>
  51
  52 #include <mLib/bits.h>
  53
  54 /*----- Magical numbers ---------------------------------------------------*/
  55
  56 #define SAFER_BLKSZ 8
  57 #define SAFER_KEYSZ 8
  58 #define SAFER_CLASS (N, B, 64)
  59
  60 #define SAFERSK_BLKSZ SAFER_BLKSZ
  61 #define SAFERSK_KEYSZ 16
  62 #define SAFERSK_CLASS SAFER_CLASS
  63
  64 #define SAFER_MAXROUNDS 12
  65
  66 extern const octet safer_keysz[];
  67 #define safersk_keysz safer_keysz
  68
  69 /*----- Data structures ---------------------------------------------------*/
  70
  71 typedef struct safer_ctx {
  72   octet k[8 * (2 * SAFER_MAXROUNDS + 1)];
  73   unsigned r;
  74 } safer_ctx, safersk_ctx;
  75
  76 /*----- Functions provided ------------------------------------------------*/
  77
  78 /* --- @safer_setup@ --- *
  79  *
  80  * Arguments:   @safer_ctx *k@ = pointer to context to initialize
  81  *              @unsigned r@ = number of rounds wanted
  82  *              @unsigned f@ = various other flags
  83  *              @const void *buf@ = pointer to key material
  84  *              @size_t sz@ = size of key material in bytes
  85  *
  86  * Returns:     ---
  87  *
  88  * Use:         Initializes an SAFER expanded key.  A default number of
  89  *              rounds is chosen, based on the key length.
  90  */
  91
  92 #define SAFER_SK 1u
  93
  94 extern void safer_setup(safer_ctx */*k*/, unsigned /*r*/, unsigned /*f*/,
  95                         const void */*buf*/, size_t /*sz*/);
  96
  97 /* --- @safer_init@, @safersk_init@ --- *
  98  *
  99  * Arguments:   @safer_ctx *k@ = pointer to context to initialize
 100  *              @const void *buf@ = pointer to key material
 101  *              @size_t sz@ = size of key material in bytes
 102  *
 103  * Returns:     ---
 104  *
 105  * Use:         Initializes an SAFER expanded key.  A default number of
 106  *              rounds is chosen, based on the key length.
 107  */
 108
 109 extern void safer_init(safer_ctx */*k*/,
 110                        const void */*buf*/, size_t /*sz*/);
 111 extern void safersk_init(safer_ctx */*k*/,
 112                          const void */*buf*/, size_t /*sz*/);
 113
 114 /* --- @safer_eblk@, @safer_dblk@ --- *
 115  *
 116  * Arguments:   @const safer_ctx *k@ = pointer to SAFER context
 117  *              @const uint32 s[2]@ = pointer to source block
 118  *              @const uint32 d[2]@ = pointer to destination block
 119  *
 120  * Returns:     ---
 121  *
 122  * Use:         Low-level block encryption and decryption.
 123  */
 124
 125 extern void safer_eblk(const safer_ctx */*k*/,
 126                        const uint32 */*s*/, uint32 */*dst*/);
 127 extern void safer_dblk(const safer_ctx */*k*/,
 128                        const uint32 */*s*/, uint32 */*dst*/);
 129
 130 #define safersk_eblk safer_eblk
 131 #define safersk_dblk safer_dblk
 132
 133 /*----- That's all, folks -------------------------------------------------*/
 134
 135 #ifdef __cplusplus
 136   }
 137 #endif
 138
 139 #endif