stringencrypter.java

java 文件下载器。可自定义

// Decompiled by Jad v1.5.8e2. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://kpdus.tripod.com/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi space 
// Source File Name:   StringEncrypter.java

package org.gudy.azureus2.ui.console.util;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.KeySpec;
import javax.crypto.*;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;
import org.bouncycastle.util.encoders.Base64;

public class StringEncrypter
{
	public static class EncryptionException extends Exception
	{

		private static final long serialVersionUID = 0x8651debb7d8cf6ceL;

		public EncryptionException(Throwable t)
		{
			super(t);
		}
	}


	public static final String DESEDE_ENCRYPTION_SCHEME = "DESede";
	public static final String DES_ENCRYPTION_SCHEME = "DES";
	public static final String DEFAULT_ENCRYPTION_KEY = "Azureus users love their sensitive information to be encrypted";
	private KeySpec keySpec;
	private SecretKeyFactory keyFactory;
	private Cipher cipher;
	private static final String UNICODE_FORMAT = "UTF8";

	public StringEncrypter(String encryptionScheme)
		throws EncryptionException
	{
		this(encryptionScheme, "Azureus users love their sensitive information to be encrypted");
	}

	public StringEncrypter(String encryptionScheme, String encryptionKey)
		throws EncryptionException
	{
		if (encryptionKey == null)
			throw new IllegalArgumentException("encryption key was null");
		if (encryptionKey.trim().length() < 24)
			throw new IllegalArgumentException("encryption key was less than 24 characters");
		try
		{
			byte keyAsBytes[] = encryptionKey.getBytes("UTF8");
			if (encryptionScheme.equals("DESede"))
				keySpec = new DESedeKeySpec(keyAsBytes);
			else
			if (encryptionScheme.equals("DES"))
				keySpec = new DESKeySpec(keyAsBytes);
			else
				throw new IllegalArgumentException((new StringBuilder()).append("Encryption scheme not supported: ").append(encryptionScheme).toString());
			keyFactory = SecretKeyFactory.getInstance(encryptionScheme);
			cipher = Cipher.getInstance(encryptionScheme);
		}
		catch (InvalidKeyException e)
		{
			throw new EncryptionException(e);
		}
		catch (UnsupportedEncodingException e)
		{
			throw new EncryptionException(e);
		}
		catch (NoSuchAlgorithmException e)
		{
			throw new EncryptionException(e);
		}
		catch (NoSuchPaddingException e)
		{
			throw new EncryptionException(e);
		}
	}

	public String encrypt(String unencryptedString)
		throws EncryptionException
	{
		if (unencryptedString == null || unencryptedString.trim().length() == 0)
			throw new IllegalArgumentException("unencrypted string was null or empty");
		byte ciphertext[];
		javax.crypto.SecretKey key = keyFactory.generateSecret(keySpec);
		cipher.init(1, key);
		byte cleartext[] = unencryptedString.getBytes("UTF8");
		ciphertext = cipher.doFinal(cleartext);
		return new String(Base64.encode(ciphertext));
		Exception e;
		e;
		throw new EncryptionException(e);
	}

	public String decrypt(String encryptedString)
		throws EncryptionException
	{
		if (encryptedString == null || encryptedString.trim().length() <= 0)
			throw new IllegalArgumentException("encrypted string was null or empty");
		byte ciphertext[];
		javax.crypto.SecretKey key = keyFactory.generateSecret(keySpec);
		cipher.init(2, key);
		byte cleartext[] = Base64.decode(encryptedString);
		ciphertext = cipher.doFinal(cleartext);
		return bytes2String(ciphertext);
		Exception e;
		e;
		throw new EncryptionException(e);
	}

	private static String bytes2String(byte bytes[])
	{
		StringBuffer stringBuffer = new StringBuffer();
		for (int i = 0; i < bytes.length; i++)
			stringBuffer.append((char)bytes[i]);

		return stringBuffer.toString();
	}
}