//This program is free software: you can redistribute it and/or modify it under the terms #of the GNU General Public License as published by the Free Software Foundation, either #version 3 of the License, or (at your option) any later version.
//This program is distributed in the hope that it will be useful, but WITHOUT ANY #WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A #PARTICULAR PURPOSE. See the GNU General Public License for more details.
//You should have received a copy of the GNU General Public License along with this #program. If not, see <http://www.gnu.org/licenses/>
#ifndef IDEA_H
#define IDEA_H

/*
 *	idea.h - header file for idea.c
 */

#include "usuals.h"  /* typedefs for byte, word16, boolean, etc. */


#define IDEAKEYSIZE 16
#define IDEABLOCKSIZE 8

#define IDEAROUNDS 8
#define IDEAKEYLEN (6*IDEAROUNDS+4)

/*
 * iv[] is used as a circular buffer.  bufleft is the number of
 * bytes at the end which have to be filled in before we crank
 * the block cipher again.  We do the block cipher operation
 * lazily: bufleft may be 0.  When we need one more byte, we
 * crank the block cipher and set bufleft to 7.
 */
struct IdeaCfbContext {
        byte iv[8];
        word16 key[IDEAKEYLEN];
        int bufleft;
};

struct IdeaRandContext {
        byte outbuf[8];
        word16 key[IDEAKEYLEN];
        int bufleft;
        byte internalbuf[8];
        byte timestamp[8];
};

void ideaCfbReinit(struct IdeaCfbContext *context, byte const *iv);
void ideaCfbInit(struct IdeaCfbContext *context, byte const (key[16]));
void ideaCfbDestroy(struct IdeaCfbContext *context);
void ideaCfbEncrypt(struct IdeaCfbContext *context,
                    byte const *src, byte *dest, int count);
void ideaCfbDecrypt(struct IdeaCfbContext *context,
                    byte const *src, byte *dest, int count);
void ideaRandInit(struct IdeaRandContext *context, byte const (key[16]),
                  byte const (seed[8]), word32 timestamp);
byte ideaRandByte(struct IdeaRandContext *c);
char **
crypt_help_idea ();

/*
   crypt_key:
   Get the key from the passed string (that may be a file name in some
   implementations) or from a key file name.  Return 0 on success but
   exit on error.
*/

int
crypt_key_idea (int key_type, char *key_text);
/*
   crypt_key_erase:
   If a local copy of the key has been made, erase it from memory.
   This increases security that the key can not be obtained from
   an examination of memory.
*/

void
crypt_key_erase_idea ();

/*
    crypt_select:
    If encryption and decryption require different ciphers,
    this routine defines the direction.  Valid choices are
    ENCRYPTION_SELECT and DECRYPTION_SELECT.
*/

int
crypt_select_idea (int selection);

/*
    crypt_file:
    encrypt or decrypt the source to the destination file.
    Do not exit from this routine.  Return 0 on success
    and return 1 on error.  Use an fprintf(stderr, ... ) to
    report the nature of the error and close any open files.
    This allows the main routine to do some cleanup before
    exiting.
*/

int
crypt_file_idea (char *source, char *dest);

#endif // IDEA_H