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());   } }