/*

 * 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 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 General Public License for more

 * details.

 * 

 * You should have received a copy of the GNU General Public License along with

 * this program. If not, see <http://www.gnu.org/licenses/>.

 */



package loginserver.network.ncrypt;



import java.security.GeneralSecurityException;

import java.security.KeyPairGenerator;

import java.security.spec.RSAKeyGenParameterSpec;



import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;



import org.apache.log4j.Logger;

import commons.utils.Rnd;



/**

 * Key generator. It generates keys or keyPairs for Blowfish and RSA

 */



public class KeyGen

{

	/**

	 * Logger for this class.

	 */

	protected static final Logger	log = Logger.getLogger(KeyGen.class);



	/**

	 * Key generator for blowfish

	 */

	private static KeyGenerator		blowfishKeyGen;



	/**

	 *  Public/Static RSA KeyPairs with encrypted modulus N

	 */

	private static EncryptedRSAKeyPair[] encryptedRSAKeyPairs;



    /**

	 * Initialize Key Generator (Blowfish keygen and RSA keygen)

	 *

	 * @throws GeneralSecurityException

	 */

	public static void init() throws GeneralSecurityException

	{

		log.info("Iniciando el generador de claves de acceso..");



		blowfishKeyGen = KeyGenerator.getInstance("Blowfish");



		KeyPairGenerator		rsaKeyPairGenerator = KeyPairGenerator.getInstance("RSA");



		RSAKeyGenParameterSpec	spec                = new RSAKeyGenParameterSpec(1024, RSAKeyGenParameterSpec.F4);



		rsaKeyPairGenerator.initialize(spec);



		encryptedRSAKeyPairs = new EncryptedRSAKeyPair[10];



		for(int i = 0; i < 10; i++)

		{

			encryptedRSAKeyPairs[i] = new EncryptedRSAKeyPair(rsaKeyPairGenerator.generateKeyPair());

		}



		// Pre-init RSA cipher.. saving about 300ms

		Cipher	rsaCipher = Cipher.getInstance("RSA/ECB/nopadding");



		rsaCipher.init(Cipher.DECRYPT_MODE, encryptedRSAKeyPairs[0].getRSAKeyPair().getPrivate());

	}



	/**

	 * Generate and return blowfish key

	 *

	 * @return Random generated blowfish key

	 */

	public static SecretKey generateBlowfishKey()

	{

		return blowfishKeyGen.generateKey();

	}



	/**

	 * Get common RSA Public/Static Key Pair with encrypted modulus N

	 * @return encryptedRSAkeypairs

	 */

	public static EncryptedRSAKeyPair getEncryptedRSAKeyPair()

	{

		return encryptedRSAKeyPairs[Rnd.nextInt(10)];

	}

}