Java中3DES加密解密调用示例

在java中调用sun公司提供的3DES加密解密算法时，需要使用到$JAVA_HOME/jre/lib/目录下如下的4个jar包：

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：

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
&
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)));

}

}