[J2SE]Java中3DES加密解密调用示例

jce.jar
security/us_export_policy.jar
security/local_policy.jar
ext/sunjce_provider.jar
java运行时会自动加载这些包，因此对于带main函数的应用程序不需要设置到classpath环境变量中。对于web应用，不需要把这些包加到web-inf/lib目录下。
以下是java中调用sun公司提供的3des加密解密算法的样本代码：

/*字符串 desede(3des) 加密*/
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.secretkeyspec;
public class threedes {
private static final string algorithm = "desede"; //定义 加密算法,可用 des,desede,blowfish

//keybyte为加密密钥，长度为24字节
//src为被加密的数据缓冲区（源）
public static byte[] encryptmode(byte[] keybyte, byte[] src) {
try {
//生成密钥
secretkey deskey = new secretkeyspec(keybyte, algorithm);
//加密
cipher c1 = cipher.getinstance(algorithm);
c1.init(cipher.encrypt_mode, deskey);
return c1.dofinal(src);
}
catch (java.security.nosuchalgorithmexception e1) {
e1.printstacktrace();
}
catch (javax.crypto.nosuchpaddingexception e2) {
e2.printstacktrace();
}
catch (java.lang.exception e3) {
e3.printstacktrace();
}
return null;
}

//keybyte为加密密钥，长度为24字节
//src为加密后的缓冲区
public static byte[] decryptmode(byte[] keybyte, byte[] src) {
try {
//生成密钥
secretkey deskey = new secretkeyspec(keybyte, algorithm);
//解密
cipher c1 = cipher.getinstance(algorithm);
c1.init(cipher.decrypt_mode, deskey);
return c1.dofinal(src);
}
catch (java.security.nosuchalgorithmexception e1) {
e1.printstacktrace();
}
catch (javax.crypto.nosuchpaddingexception e2) {
e2.printstacktrace();
}
catch (java.lang.exception e3) {
e3.printstacktrace();
}
return null;
}

//转换成十六进制字符串
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){

//添加新安全算法,如果用jce就要把它添加进去
security.addprovider(new com.sun.crypto.provider.sunjce());
final byte[] keybytes = {0x11, 0x22, 0x4f, 0x58,
(byte)0x88, 0x10, 0x40, 0x38, 0x28, 0x25, 0x79, 0x51,
(byte)0xcb, (byte)0xdd, 0x55, 0x66, 0x77, 0x29, 0x74,
(byte)0x98, 0x30, 0x40, 0x36, (byte)0xe2
}; //24字节的密钥

string szsrc = "this is a 3des test. 测试";
system.out.println("加密前的字符串:" + szsrc);

byte[] encoded = encryptmode(keybytes, szsrc.getbytes());
system.out.println("加密后的字符串:" + new string(encoded));

byte[] srcbytes = decryptmode(keybytes, encoded);
system.out.println("解密后的字符串:" + (new string(srcbytes)));
}
}