求加密字符串函数！

Question

简单的DES加解密
import java.security.*;
import javax.crypto.*;public class Crypt
{    private static String Algorithm = "DES"; //定义 加密算法,可用 DES,DESede,Blowfish    static boolean debug = false;    static
    {
        Security.addProvider(new com.sun.crypto.provider.SunJCE());
    }    //生成密钥, 注意此步骤时间比较长
    public static byte[] getKey()
        throws Exception
    {
        KeyGenerator keygen = KeyGenerator.getInstance(Algorithm);
        SecretKey deskey = keygen.generateKey();
        if (debug)
            System.out.println("生成密钥:" + byte2hex(deskey.getEncoded()));
        return deskey.getEncoded();
    }    //加密
    public static byte[] encode(byte[] input, byte[] key)
        throws Exception
    {
        SecretKey deskey = new javax.crypto.spec.SecretKeySpec(key, Algorithm);
        if (debug)
        {
            System.out.println("加密前的二进串:" + byte2hex(input));
            System.out.println("加密前的字符串:" + new String(input));
        }
        Cipher c1 = Cipher.getInstance(Algorithm);
        c1.init(Cipher.ENCRYPT_MODE, deskey);
        byte[] cipherByte = c1.doFinal(input);
        if (debug)
            System.out.println("加密后的二进串:" + byte2hex(cipherByte));
        return cipherByte;
    }    //解密
    public static byte[] decode(byte[] input, byte[] key)
        throws Exception
    {
        SecretKey deskey = new javax.crypto.spec.SecretKeySpec(key, Algorithm);
        if (debug)
            System.out.println("解密前的信息:" + byte2hex(input));
        Cipher c1 = Cipher.getInstance(Algorithm);
        c1.init(Cipher.DECRYPT_MODE, deskey);
        byte[] clearByte = c1.doFinal(input);
        if (debug)
        {
            System.out.println("解密后的二进串:" + byte2hex(clearByte));
            System.out.println("解密后的字符串:" + (new String(clearByte)));
        }
        return clearByte;
    }    //md5()信息摘要, 不可逆
    public static byte[] md5(byte[] input)
        throws Exception
    {
        java.security.MessageDigest alg = java.security.MessageDigest.
            getInstance("MD5"); //or "SHA-1"
        if (debug)
        {
            System.out.println("摘要前的二进串:" + byte2hex(input));
            System.out.println("摘要前的字符串:" + new String(input));
        }
        alg.update(input);
        byte[] digest = alg.digest();
        if (debug)
            System.out.println("摘要后的二进串:" + byte2hex(digest));
        return digest;
    }    //字节码转换成16进制字符串
    public static String byte2hex(byte[] b)
    {
        String hs = "";
        String stmp = "";
        for (int n = 0; n < b.length; n++)
        {
            stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
            if (stmp.length() == 1)
                hs = hs + "0" + stmp;
            else
                hs = hs + stmp;
            if (n < b.length - 1)
                hs = hs + ":";
        }
        return hs.toUpperCase();
    }
/*
    public static void main(String[] args)
        throws Exception
    {
        debug = true;
//    byte[] key = getKey();
        byte[] key = "好好学习".getBytes();
        decode(encode("测试加密".getBytes(), key), key);
        md5("测试加密".getBytes());
    }
*/
}