简单加密解密方法包装, 含encode(),decode(),md5()

package steeven;/*用途: 简单加密/解密方法包装作者: steeven@kali.com.cn日期: 12/05/2001感谢: http://www-900.ibm.com/developerWorks/java/l-security/index.shtml说明:This Class need JCE, download here:http://java.sun.com/security/index.html*/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());  }}