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());
}
}
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