[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))); 
} 
}