passwordutil.java

来自「Java mulitplayer strategy game. Adaptati」· Java 代码 · 共 102 行

package net.sf.jawp.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * Simple utility for CHAP protocol and password manipulation.
 * 
 * protocol explanation 1. a) server has encoded pass for user b) user knows his
 * pass 2. server sends random string to client - (and stores it) 3. client
 * encodes his pass, adds string form server... and encoded both again - sends
 * result to server 4. server does some as above (apart from that it alredy has
 * encoded client pass) server compares its result with the one sent by client
 * 
 * @author jarek
 * @version $Revision: 1.8 $
 * 
 */
public final class PasswordUtil
{
	private static final Log LOG = Log.getLog(PasswordUtil.class);

	private static final String PASSWORD_ENCODING = "UTF-8";
//	private static final MessageDigest MD;

	private static final SecureRandom RANDOM;

	static
	{
		try
		{
			//MD = MessageDigest.getInstance("SHA");
			RANDOM = SecureRandom.getInstance("SHA1PRNG");
		}
		catch (final Throwable t)
		{
			LOG.error(t, t);
			throw new RuntimeException(t);
		}
	}

	private PasswordUtil()
	{
	}

	private static MessageDigest getMessageDigest()
	{
		try
		{
			return MessageDigest.getInstance("SHA");
		}
		catch (final NoSuchAlgorithmException e)
		{
			LOG.error(e, e);
			throw new RuntimeException(e);
		}
	}
	
	/**
	 * this ecrypts password using one of statndard funkctions
	 */
	public static String encrypt(final String anOrig)
	{
		try
		{
			final byte[] todig = anOrig.getBytes(PASSWORD_ENCODING);
			final byte[] res = getMessageDigest().digest(todig);
			return new String(res, PASSWORD_ENCODING);
		}
		catch (final UnsupportedEncodingException uoe)
		{
			throw new UnsupportedOperationException ("encoding:" + PASSWORD_ENCODING + " unknown"); 
			
		}
	}

	/**
	 * 
	 * 
	 */

	public static String encryptMix(final String anEncrypted, final String seed)
	{
		return encrypt(anEncrypted + seed);
	}

	public static boolean checkPass(final String aMixed, final String seed,
			final String encrypted)
	{
		return aMixed.equals(encryptMix(encrypted, seed));
	}

	public static String generateRandomSeed()
	{
		final byte[] secureBT = new byte[10];
		RANDOM.nextBytes(secureBT);
		return new String(secureBT);
	}
}