Java - 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
& 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());


}


}