org.starnub.utilities.crypto.PasswordHash.java Source code

Introduction

Here is the source code for org.starnub.utilities.crypto.PasswordHash.java

Source

/*
 * Copyright (C) 2014 www.StarNub.org - Underbalanced
 *
 * This file is part of org.starnub a Java Wrapper for Starbound.
 *
 * This above mentioned StarNub software 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
 * any later version. This above mentioned CodeHome software
 * 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 in
 * this StarNub Software.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.starnub.utilities.crypto;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import java.security.SecureRandom;

/**
 *
 */
public class PasswordHash {

    /**
     * The higher the number of iterations the more
     * expensive computing the hash is for us
     * and also for a brute force attack.
     */
    private final int iterations = 10 * 1024;
    private final int saltLen = 32;
    private final int desiredKeyLen = 256;

    /**
     * Computes a salted PBKDF2 hash of given plaintext password
     * suitable for storing in a database.
     * Empty passwords are not supported.
     * @param password String password to be hashed
     * @return String of salted password
     * @throws Exception
     */
    public String getSaltedHash(String password) throws Exception {
        byte[] salt = SecureRandom.getInstance("SHA1PRNG").generateSeed(saltLen);
        // store the salt with the password
        return Base64.encodeBase64String(salt) + "$" + hash(password, salt);
    }

    /**
     * Checks whether given plaintext password corresponds
     * to a stored salted hash of the password.
     * @param password String password to be checked
     * @param stored String of stored salted password
     * @return boolean match
     * @throws Exception
     */
    public boolean check(String password, String stored) throws Exception {
        String[] saltAndPass = stored.split("\\$");
        if (saltAndPass.length != 2)
            return false;
        String hashOfInput;
        hashOfInput = hash(password, Base64.decodeBase64(saltAndPass[0]));
        return hashOfInput.equals(saltAndPass[1]);
    }

    /**
     * using PBKDF2 from Sun, an alternative is https://github.com/wg/scrypt
     * cf. http://www.unlimitednovelty.com/2012/03/dont-use-bcrypt.html
     * @param password String password to be salted
     * @param salt Byte[] of the salt
     * @return String of the hashed password
     * @throws Exception
     */
    private String hash(String password, byte[] salt) throws Exception {
        if (password == null || password.length() == 0)
            throw new IllegalArgumentException("Empty passwords are not supported.");
        SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        SecretKey key = f.generateSecret(new PBEKeySpec(password.toCharArray(), salt, iterations, desiredKeyLen));
        return Base64.encodeBase64String(key.getEncoded());
    }
}