/**
 * @file crypter.h
 * 
 * @brief Interface of crypter_t
 * 
 */

/*
 * Copyright (C) 2005 Jan Hutter, Martin Willi
 * Hochschule fuer Technik Rapperswil
 *
 * 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 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * 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.
 */

#ifndef CRYPTER_H_
#define CRYPTER_H_

#include <types.h>

typedef enum encryption_algorithm_t encryption_algorithm_t;

/**
 * @brief Encryption algorithm, as in IKEv2 draft 3.3.2
 */
enum encryption_algorithm_t {
	ENCR_UNDEFINED = 1024,
	ENCR_DES_IV64 = 1,
	ENCR_DES = 2,
	ENCR_3DES = 3,
	ENCR_RC5 = 4,
	ENCR_IDEA = 5,
	ENCR_CAST = 6,
	ENCR_BLOWFISH = 7,
	ENCR_3IDEA = 8,
	ENCR_DES_IV32 = 9,
	RESERVED = 10,
	ENCR_NULL = 11,
	ENCR_AES_CBC = 12,
	ENCR_AES_CTR = 13
};

/** 
 * string mappings for encryption_algorithm_t
 */
extern mapping_t encryption_algorithm_m[];

typedef struct crypter_t crypter_t;

/**
 * @brief Generic interface for symmetric encryption algorithms.
 * 
 * @ingroup crypters
 */
struct crypter_t {
	/**
	 * @brief Encrypt a chunk of data and allocate space for 
	 * the encrypted value.
	 * 
	 * @param this				calling crypter
	 * @param data				data to encrypt
	 * @param iv					iv
	 * @param [out]encrypted	pointer where the encrypted bytes will be written
	 * @return
	 * 							- SUCCESS, or
	 * 							- INVALID_ARG if data size not a multiple of  block size
	 */
	status_t (*encrypt) (crypter_t *this, chunk_t data, chunk_t iv, chunk_t *encrypted);
	
	/**
	 * @brief Decrypt a chunk of data and allocate space for 
	 * the decrypted value.
	 * 
	 * @param this				calling crypter
	 * @param data				data to decrypt
	 * @param iv					iv
	 * @param [out]encrypted	pointer where the decrypted bytes will be written
	 * @return
	 * 							- SUCCESS, or
	 * 							- INVALID_ARG if data size not a multiple of  block size
	 */
	status_t (*decrypt) (crypter_t *this, chunk_t data, chunk_t iv, chunk_t *decrypted);

	/**
	 * @brief get the block size of this crypter
	 * 
	 * @param this				calling crypter
	 * @return					block size in bytes
	 */
	size_t (*get_block_size) (crypter_t *this);
	
	/**
	 * @brief Set the key for this crypter
	 * 
	 * @param this				calling crypter
	 * @param key				key to set
	 * @return
	 * 							- SUCCESS, or
	 * 							- INVALID_ARG if key size != block size
	 */
	status_t (*set_key) (crypter_t *this, chunk_t key);
	
	/**
	 * @brief Destroys a crypter_t object.
	 *
	 * @param this 				crypter_t object to destroy
	 */
	void (*destroy) (crypter_t *this);
};

/**
 * @brief Generic constructor for crypter_t objects.
 * 
 * @param encryption_algorithm	Algorithm to use for crypter
 * @param blocksize 				block size in bytes
 * @return
 * 								- crypter_t if successfully
 * 								- NULL if crypter not supported
 */
crypter_t *crypter_create(encryption_algorithm_t encryption_algorithm, size_t blocksize);

#endif /*CRYPTER_H_*/