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/**
* @file hasher.h
*
* @brief Interface hasher_t.
*
*/
/*
* Copyright (C) 2005-2006 Martin Willi
* Copyright (C) 2005 Jan Hutter
* 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 HASHER_H_
#define HASHER_H_
typedef enum hash_algorithm_t hash_algorithm_t;
typedef struct hasher_t hasher_t;
#include <library.h>
/**
* @brief Algorithms to use for hashing.
*
* Currently only the following algorithms are implemented:
* - HASH_MD5
* - HASH_SHA1
* - HASH_SHA256
* - HASH_SHA384
* - HASH_SHA512
*
* @ingroup hashers
*/
enum hash_algorithm_t {
HASH_MD2 = 0,
/** Implemented in class md5_hasher_t */
HASH_MD5 = 1,
/** Implemented in class sha1_hasher_t */
HASH_SHA1 = 2,
/** Implemented in class sha2_hasher_t */
HASH_SHA256 = 3,
/** Implemented in class sha2_hasher_t */
HASH_SHA384 = 4,
/** Implemented in class sha2_hasher_t */
HASH_SHA512 = 5,
};
#define HASH_SIZE_MD2 16
#define HASH_SIZE_MD5 16
#define HASH_SIZE_SHA1 20
#define HASH_SIZE_SHA256 32
#define HASH_SIZE_SHA384 48
#define HASH_SIZE_SHA512 64
#define HASH_SIZE_MAX 64
/**
* enum names for hash_algorithm_t.
*/
extern enum_name_t *hash_algorithm_names;
/**
* @brief Generic interface for all hash functions.
*
* @b Constructors:
* - hasher_create()
*
* @ingroup hashers
*/
struct hasher_t {
/**
* @brief Hash data and write it in the buffer.
*
* If the parameter hash is NULL, no result is written back
* an more data can be appended to already hashed data.
* If not, the result is written back and the hasher is reset.
*
* The hash output parameter must hold at least
* hash_t.get_block_size() bytes.
*
* @param this calling object
* @param data data to hash
* @param[out] hash pointer where the hash will be written
*/
void (*get_hash) (hasher_t *this, chunk_t data, u_int8_t *hash);
/**
* @brief Hash data and allocate space for the hash.
*
* If the parameter hash is NULL, no result is written back
* an more data can be appended to already hashed data.
* If not, the result is written back and the hasher is reset.
*
* @param this calling object
* @param data chunk with data to hash
* @param[out] hash chunk which will hold allocated hash
*/
void (*allocate_hash) (hasher_t *this, chunk_t data, chunk_t *hash);
/**
* @brief Get the size of the resulting hash.
*
* @param this calling object
* @return hash size in bytes
*/
size_t (*get_hash_size) (hasher_t *this);
/**
* @brief Resets the hashers state.
*
* @param this calling object
*/
void (*reset) (hasher_t *this);
/**
* @brief Get the state of the hasher.
*
* A hasher stores internal state information. This state may be
* manipulated to include a "seed" into the hashing operation. It used by
* some exotic protocols (such as AKA).
* The data pointed by chunk may be manipulated, but not replaced nor freed.
* This is more a hack than a feature. The hasher's state may be byte
* order dependant; use with care.
*
* @param this calling object
*/
chunk_t (*get_state) (hasher_t *this);
/**
* @brief Destroys a hasher object.
*
* @param this calling object
*/
void (*destroy) (hasher_t *this);
};
/**
* @brief Generic interface to create a hasher_t.
*
* @param hash_algorithm Algorithm to use for hashing
* @return
* - hasher_t object
* - NULL if algorithm not supported
*
* @ingroup hashers
*/
hasher_t *hasher_create(hash_algorithm_t hash_algorithm);
#endif /* HASHER_H_ */
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