/*! \file picrypt.h
 * \brief Cryptographic class using lib Sodium
*/
/*
	PIP - Platform Independent Primitives
	Cryptographic class using lib Sodium
	Andrey Bychkov work.a.b@yandex.ru

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser 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 Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef PICRYPT_H
#define PICRYPT_H

#include "pip_crypt_export.h"
#include "pistring.h"

class PIP_CRYPT_EXPORT PICrypt {
public:
	//! Construct and generate random key
	PICrypt();

	//! Set key to "key", key size must be a \a sizeKey()
	bool setKey(const PIByteArray & key);

	//! Generate and set key from keyphrase "secret"
	PIByteArray setKey(const PIString & secret);

	//! Returns current key
	PIByteArray key() {return key_;}

	//! Encrypt given data "data", result size will be increased by \a sizeCrypt()
	PIByteArray crypt(const PIByteArray & data);

	//! Decrypt given data "crypt_data"
	PIByteArray decrypt(const PIByteArray & crypt_data, bool * ok = 0);

	//! Encrypt given data "data" with key "key", result size will be increased by \a sizeCrypt()
	static PIByteArray crypt(const PIByteArray & data, PIByteArray key);

	//! Decrypt given data "crypt_data" with key "key"
	static PIByteArray decrypt(const PIByteArray & crypt_data, PIByteArray key, bool * ok = 0);

	//! Generate hash from keyphrase "secret", may be used as a key for encryption
	static PIByteArray hash(const PIString & secret);

	//! Generate hash from bytearray
	static PIByteArray hash(const PIByteArray & data);

	//! Generate hash from bytearray
	static PIByteArray hash(const PIByteArray & data, const unsigned char * key, size_t keylen);

	//! Returns hash size
	static size_t sizeHash();

	//! Generate short hash from string "s", may be used for hash table
	static ullong shorthash(const PIString & s, PIByteArray key = PIByteArray());

	//! Generate random key
	static PIByteArray generateKey();

	//! Generate random buffer
	static PIByteArray generateRandomBuff(int size);

	//! Returns key size
	static size_t sizeKey();

	//! Returns size which be added to data size in encryption process
	static size_t sizeCrypt();

	//! Function randomly generates a secret key and a corresponding public key for digital signature
	static void generateSignKeys(PIByteArray & public_key, PIByteArray & secret_key);

	//! Function generates a secret key from input data and a corresponding public key for digital signature
	static void generateSignKeys(PIByteArray & public_key, PIByteArray & secret_key, const PIByteArray & seed);

	//! Function extract sign public key from sing secret key
	static PIByteArray extractSignPublicKey(const PIByteArray & secret_key);

	//! Calculate digital signature for data
	PIByteArray signMessage(const PIByteArray & data,  PIByteArray secret_key);

	//! Verify digital signature of signed message
	bool verifySign(const PIByteArray & data, const PIByteArray & signature, PIByteArray public_key);

	//! Function randomly generates a secret key and a corresponding public key for authenticated encryption
	static void generateKeypair(PIByteArray & public_key, PIByteArray & secret_key);

	//! Function generates a secret key from input data and a corresponding public key for authenticated encryption
	static void generateKeypair(PIByteArray & public_key, PIByteArray & secret_key, const PIByteArray & seed);

	//! Encrypt given data "data"
	PIByteArray crypt(const PIByteArray &data, const PIByteArray & public_key, const PIByteArray & secret_key);

	//! Decrypt given data "crypt_data"
	PIByteArray decrypt(const PIByteArray & crypt_data, const PIByteArray & public_key, const PIByteArray & secret_key, bool * ok = 0);

	//! Generate password hash from "password"
	static PIByteArray passwordHash(const PIString & password, const PIByteArray & seed);

	//! Returns libsodium version
	static PIString version();


private:
	static bool init();

	PIByteArray nonce_, key_;

};

#endif // PICRYPT_H