/*

cipher.h

Author: Tatu Ylonen <ylo@ssh.fi>

Copyright (c) 1995 Tatu Ylonen <ylo@ssh.fi>, Espoo, Finland
Copyright (c) 1995-1999 SSH Communications Security Oy, Espoo, Finland
                        All rights reserved

Created: Wed Apr 19 16:50:42 1995 ylo

*/

/*
 * $Id: cipher.h,v 1.10 1999/11/17 17:04:42 tri Exp $
 * $Log: cipher.h,v $
 * Revision 1.10  1999/11/17 17:04:42  tri
 * 	Fixed copyright notices.
 *
 * Revision 1.9  1998/04/30 01:51:26  kivinen
 *      Reserved cipher number 7 to Bernard Perrot
 *      <perrot@lal.in2p3.fr> for some weak 40 bit encryption method.
 *
 * Revision 1.8  1998/03/27 17:24:03  kivinen
 *      Removed TSS.
 *
 * Revision 1.7  1997/03/26 07:11:22  kivinen
 *      Fixed prototypes.
 *
 * Revision 1.6  1997/03/19 22:26:24  kivinen
 *      Removed WITH_3DES ifdefs, as it is mandatory.
 *
 * Revision 1.5  1997/03/19 17:35:09  kivinen
 *      Made all ciphers optional.
 *
 * Revision 1.4  1996/09/28 12:01:15  ylo
 *      Removed TSS (put inside #ifdef WITH_TSS).
 *
 * Revision 1.3  1996/09/27 13:55:03  ttsalo
 *      Added blowfish
 *
 * Revision 1.2  1996/02/18 21:52:35  ylo
 *      Added comments that len must be multiple of 8.
 *
 * Revision 1.1.1.1  1996/02/18 21:38:11  ylo
 *      Imported ssh-1.2.13.
 *
 * Revision 1.3  1995/08/18  22:48:27  ylo
 *      Made IDEA optional.
 *
 * Revision 1.2  1995/07/13  01:19:52  ylo
 *      Removed "Last modified" header.
 *      Added cvs log.
 *
 * $Endlog$
 */

#ifndef CIPHER_H
#define CIPHER_H

#ifndef WITHOUT_IDEA
#include "idea.h"
#endif /* WITHOUT_IDEA */
#include "des.h"
#ifdef WITH_ARCFOUR
#include "arcfour.h"
#endif /* WITH_ARCFOUR */
#ifdef WITH_BLOWFISH
#include "blowfish.h"
#endif /* WITH_BLOWFISH */

/* Cipher types.  New types can be added, but old types should not be removed
   for compatibility.  The maximum allowed value is 31. */
#define SSH_CIPHER_NOT_SET      -1 /* None selected (invalid number). */
#define SSH_CIPHER_NONE         0 /* no encryption */
#define SSH_CIPHER_IDEA         1 /* IDEA CFB */
#define SSH_CIPHER_DES          2 /* DES CBC */
#define SSH_CIPHER_3DES         3 /* 3DES CBC */
#define SSH_CIPHER_ARCFOUR      5 /* Arcfour */
#define SSH_CIPHER_BLOWFISH     6 /* Bruce Schneier's Blowfish */
#define SSH_CIPHER_RESERVED     7 /* Reserved for 40 bit crippled encryption,
                                     Bernard Perrot <perrot@lal.in2p3.fr> */

typedef struct {
  unsigned int type;
  union {
#ifndef WITHOUT_IDEA
    struct {
      IDEAContext key;
      unsigned char iv[8];
    } idea;
#endif /* WITHOUT_IDEA */
#ifdef WITH_DES
    struct {
      DESContext key;
      unsigned char iv[8];
    } des;
#endif /* WITH_DES */
    struct {
      DESContext key1;
      unsigned char iv1[8];
      DESContext key2;
      unsigned char iv2[8];
      DESContext key3;
      unsigned char iv3[8];
    } des3;
#ifdef WITH_ARCFOUR
    ArcfourContext arcfour;
#endif
#ifdef WITH_BLOWFISH
    BlowfishContext blowfish;
#endif /* WITH_BLOWFISH */
  } u;
} CipherContext;

/* Returns a bit mask indicating which ciphers are supported by this
   implementation.  The bit mask has the corresponding bit set of each
   supported cipher. */
unsigned int cipher_mask(void);

/* Returns the name of the cipher. */
const char *cipher_name(int cipher);

/* Parses the name of the cipher.  Returns the number of the corresponding
   cipher, or -1 on error. */
int cipher_number(const char *name);

/* Selects the cipher to use and sets the key.  If for_encryption is true,
   the key is setup for encryption; otherwise it is setup for decryption. */
void cipher_set_key(CipherContext *context, int cipher,
                    const unsigned char *key, int keylen, int for_encryption);

/* Sets key for the cipher by computing the MD5 checksum of the passphrase,
   and using the resulting 16 bytes as the key. */
void cipher_set_key_string(CipherContext *context, int cipher,
                           const char *passphrase, int for_encryption);

/* Encrypts data using the cipher.  For most ciphers, len should be a
   multiple of 8. */
void cipher_encrypt(CipherContext *context, unsigned char *dest,
                    const unsigned char *src, unsigned int len);

/* Decrypts data using the cipher.  For most ciphers, len should be a
   multiple of 8. */
void cipher_decrypt(CipherContext *context, unsigned char *dest,
                    const unsigned char *src, unsigned int len);

#endif /* CIPHER_H */
