001    /**
002     * Copyright (c) 2000-2013 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.kernel.security;
016    
017    import java.util.Random;
018    
019    /**
020     * @author Shuyang Zhou
021     */
022    public class SecureRandom extends Random {
023    
024            @Override
025            protected int next(int bits) {
026                    int bytes = (bits + 7) / 8;
027    
028                    int result = SecureRandomUtil.nextByte();
029    
030                    for (int i = 1; i < bytes; i++) {
031                            result = (result << 8) + (SecureRandomUtil.nextByte() & 0xFF);
032                    }
033    
034                    return result >>> (bytes * 8 - bits);
035            }
036    
037    }