mdw@git.distorted.org.uk Git - become/blob - src/idea.h

   1 /* -*-c-*-
   2  *
   3  * $Id: idea.h,v 1.1 1997/07/21 13:47:48 mdw Exp $
   4  *
   5  * IDEA encryption routines
   6  *  Based on Straylight ARM assembler routines
   7  *
   8  * (c) 1996, 1997 Mark Wooding
   9  */
  10
  11 /*----- Licencing notice --------------------------------------------------*
  12  *
  13  * This file is part of `become'
  14  *
  15  * `Become' is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation; either version 2 of the License, or
  18  * (at your option) any later version.
  19  *
  20  * `Become' is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with `become'; if not, write to the Free Software
  27  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: idea.h,v $
  33  * Revision 1.1  1997/07/21 13:47:48  mdw
  34  * Initial revision
  35  *
  36  */
  37
  38 #ifndef IDEA_H
  39 #define IDEA_H
  40
  41 #ifdef __cplusplus
  42   extern "C" {
  43 #endif
  44
  45 /*----- Required headers --------------------------------------------------*/
  46
  47 #ifndef CONFIG_H
  48 #  include "config.h"
  49 #endif
  50
  51 /*----- Useful constants --------------------------------------------------*/
  52
  53 #define IDEA_BLKSIZE (8u)               /* Number of bytes in IDEA block */
  54 #define IDEA_KEYSIZE (16u)              /* Number of bytes in IDEA key */
  55 #define IDEA_EXPKEYSIZE (52u)           /* Number of ints in expanded key */
  56
  57 /*----- Type definitions --------------------------------------------------*/
  58
  59 typedef struct idea_key {
  60   int k[IDEA_EXPKEYSIZE];               /* Subkey array */
  61 } idea_key;
  62
  63 /*----- Functions provided ------------------------------------------------*/
  64
  65 /* --- @idea_ekeys@ --- *
  66  *
  67  * Arguments:   @idea_key *k@ = the expanded key buffer
  68  *              @const unsigned char *key@ = the user's key encryption key
  69  *
  70  * Returns:     ---
  71  *
  72  * Use:         Unpacks an encryption key.
  73  */
  74
  75 extern void idea_ekeys(idea_key */*k*/, const unsigned char */*key*/);
  76
  77 /* --- @idea_invertKey@ --- *
  78  *
  79  * Arguments:   @const idea_key *in@ = pointer to input expanded key buffer
  80  *              @idea_key *out@ = pointer to output expanded key buffer
  81  *
  82  * Returns:     ---
  83  *
  84  * Use:         Computes the inverse (decryption) key given an expanded
  85  *              IDEA encryption key.
  86  */
  87
  88 extern void idea_invertKey(const idea_key */*in*/, idea_key */*out*/);
  89
  90 /* --- @idea_dkeys@ --- *
  91  *
  92  * Arguments:   @idea_key *k@ = the expanded key buffer
  93  *              @const unsigned char *key@ = the user's key encryption key
  94  *
  95  * Returns:     ---
  96  *
  97  * Use:         Unpacks a decryption key.
  98  */
  99
 100 extern void idea_dkeys(idea_key */*k*/, const unsigned char */*key*/);
 101
 102 /* --- @idea_encrypt@ --- *
 103  *
 104  * Arguments:   @const idea_key *k@ = key to use
 105  *              @const void *src@ = block to encrypt
 106  *              @void *dest@ = where to store the result
 107  *
 108  *
 109  * Returns:     ---
 110  *
 111  * Use:         Encrypts (or decrypts) a block, using the IDEA cryptosystem.
 112  *              Since the decryption operation is the same as encryption
 113  *              except that a different key buffer is used, this is all we
 114  *              need to complete the simple bits.
 115  */
 116
 117 extern void idea_encrypt(const idea_key */*k*/,
 118                          const void */*src*/, void */*dest*/);
 119
 120 /*----- That's all, folks -------------------------------------------------*/
 121
 122 #ifdef __cplusplus
 123   }
 124 #endif
 125
 126 #endif