java 采用MD5加密解密

MD5加密解密

package endecrypt;  

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

/**
 * 采用MD5加密解密
 * @author tfq
 * @datetime 2011-10-13
 */
public class MD5Util {  

    /***
     * MD5加码 生成32位md5码
     */
    public static String string2MD5(String inStr){
        MessageDigest md5 = null;
        try{
            md5 = MessageDigest.getInstance("MD5");
        }catch (Exception e){
            System.out.println(e.toString());
            e.printStackTrace();
            return "";
        }
        char[] charArray = inStr.toCharArray();
        byte[] byteArray = new byte[charArray.length];  

        for (int i = 0; i < charArray.length; i++)
            byteArray[i] = (byte) charArray[i];
        byte[] md5Bytes = md5.digest(byteArray);
        StringBuffer hexValue = new StringBuffer();
        for (int i = 0; i < md5Bytes.length; i++){
            int val = ((int) md5Bytes[i]) & 0xff;
            if (val < 16)
                hexValue.append("0");
            hexValue.append(Integer.toHexString(val));
        }
        return hexValue.toString();  

    }  

    /**
     * 加密解密算法 执行一次加密，两次解密
     */
    public static String convertMD5(String inStr){  

        char[] a = inStr.toCharArray();
        for (int i = 0; i < a.length; i++){
            a[i] = (char) (a[i] ^ 't');
        }
        String s = new String(a);
        return s;  

    }  

    // 测试主函数
    public static void main(String args[]) {
        String s = new String("tangfuqiang");
        System.out.println("原始：" + s);
        System.out.println("MD5后：" + string2MD5(s));
        System.out.println("加密的：" + convertMD5(s));
        System.out.println("解密的：" + convertMD5(convertMD5(s)));  

    }
}