/*

cipher.h

Author: Tatu Ylonen <ylo@cs.hut.fi>

Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                   All rights reserved

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

*/

/* RCSID("$Id: cipher.h,v 1.4 1999/09/28 04:45:36 provos Exp $"); */

#ifndef CIPHER_H
#define CIPHER_H

#include "des.h"
#include "blowfish.h"

/* 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_TSS		4 /* TRI's Simple Stream encryption CBC */
#define SSH_CIPHER_RC4		5 /* Alleged RC4 */
#define SSH_CIPHER_BLOWFISH	6

typedef struct {
  unsigned int type;
  union {
#ifdef WITH_DES
    struct {
      des_key_schedule key;
      des_cblock iv;
    } des;
#endif /* WITH_DES */
    struct {
      des_key_schedule key1;
      des_key_schedule key2;
      des_cblock iv2;
      des_key_schedule key3;
      des_cblock iv3;
    } des3;
    struct {
      struct bf_key_st key;
      unsigned char iv[8];
    } bf;
  } 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();

/* 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. */
void cipher_encrypt(CipherContext *context, unsigned char *dest,
		    const unsigned char *src, unsigned int len);

/* Decrypts data using the cipher. */
void cipher_decrypt(CipherContext *context, unsigned char *dest,
		    const unsigned char *src, unsigned int len);

/* If and CRC-32 attack is detected this function is called. Defaults
 * to fatal, changed to packet_disconnect in sshd and ssh. */
extern void (*cipher_attack_detected)(const char *fmt, ...);

#endif /* CIPHER_H */