com.wlami.mibox.core.encryption.PBKDF2.java Source code

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Here is the source code for com.wlami.mibox.core.encryption.PBKDF2.java

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/**
 *     MiBox Core - Common used classes
 *  Copyright (C) 2012 MiBox
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.wlami.mibox.core.encryption;

import org.bouncycastle.crypto.PBEParametersGenerator;
import org.bouncycastle.crypto.generators.PKCS5S2ParametersGenerator;
import org.bouncycastle.crypto.params.KeyParameter;

/**
 * This class provides methods for key derivation from passwords.
 */
public class PBKDF2 {

    /** Default key length in bit */
    private static final int DEFAULT_KEY_LENGTH_BIT = 256;

    /** PBKDF2 uses this number of rounds for key derivation */
    private static final int DEFAULT_KEY_TRANSFORMATION_ROUNDS = 10000;

    /** hidden constructor because this is an utility class */
    private PBKDF2() {
    }

    protected static byte[] doPbkdf2(String password, String salt, int rounds) {
        PBEParametersGenerator pbeParametersGenerator = new PKCS5S2ParametersGenerator();
        pbeParametersGenerator.init(PBEParametersGenerator.PKCS5PasswordToBytes(password.toCharArray()),
                PBEParametersGenerator.PKCS5PasswordToBytes(salt.toCharArray()), rounds);
        KeyParameter keyParameter = (KeyParameter) pbeParametersGenerator
                .generateDerivedParameters(DEFAULT_KEY_LENGTH_BIT);
        return keyParameter.getKey();
    }

    /**
     * Get an 256bit key from a given password. This key can be used for aes
     * encryption.
     * 
     * @param password
     *            The password from which the key is derived
     * @param salt
     *            salt value
     * @return returns an byte array with length 32;
     */
    public static byte[] getKeyFromPasswordAndSalt(String password, String salt) {
        return doPbkdf2(password, salt, DEFAULT_KEY_TRANSFORMATION_ROUNDS);
    }

}