【转】Java Cipher类 DES算法（加密与解密）

import java.security.*;

import javax.crypto.*;

import java.io.*;

//对称加密器
public class CipherMessage {
private String algorithm; // 算法，如DES
private Key key; // 根据算法对应的密钥
private String plainText; // 明文

KeyGenerator keyGenerator;
Cipher cipher;

// 函数进行初始化
CipherMessage(String alg, String msg) {
algorithm = alg;
plainText = msg;
}

// 加密函数，将原文加密成密文
public byte[] CipherMsg() {
byte[] cipherText = null;

try {
// 生成Cipher对象
cipher = Cipher.getInstance(algorithm);
// 用密钥加密明文(plainText),生成密文(cipherText)
cipher.init(Cipher.ENCRYPT_MODE, key); // 操作模式为加密(Cipher.ENCRYPT_MODE),key为密钥
cipherText = cipher.doFinal(plainText.getBytes()); // 得到加密后的字节数组
// String str = new String(cipherText);
} catch (Exception e) {
e.printStackTrace();
}
return cipherText;
}

// 解密函数，将密文解密回原文
public String EncipherMsg(byte[] cipherText, Key k) {
byte[] sourceText = null;

try {
cipher.init(Cipher.DECRYPT_MODE, k); // 操作模式为解密,key为密钥
sourceText = cipher.doFinal(cipherText);
} catch (Exception e) {
e.printStackTrace();
}
return new String(sourceText);

}

// 生成密钥
public Key initKey() {
try {
// 初始化密钥key
keyGenerator = KeyGenerator.getInstance(algorithm);
keyGenerator.init(56); // 选择DES算法,密钥长度必须为56位
key = keyGenerator.generateKey(); // 生成密钥
} catch (Exception ex) {
ex.printStackTrace();
}
return key;
}

// 获取Key类型的密钥
public Key getKey() {
return key;
}

// 获取Key类型的密钥
public Key getKey(byte[] k) {
try {
key = cipher.unwrap(k, algorithm, Cipher.DECRYPT_MODE);
} catch (Exception ex) {
ex.printStackTrace();
}
return key;
}

// 获取密钥包装成byte[]类型的
public byte[] getBinaryKey(Key k) {
byte[] bk = null;
try {
bk = cipher.wrap(k);
} catch (Exception ex) {
ex.printStackTrace();
}
return bk;
}
}

import java.security.*;

import javax.crypto.*;

import java.io.*;

public class TestMain {

public static void main(String[] args) {
String algorithm = "DES"; // 定义加密算法,可用 DES,DESede,Blowfish
String message = "Hello World. 这是待加密的信息"; // 生成个DES密钥
Key key;

CipherMessage cm = new CipherMessage(algorithm, message);
key = cm.initKey();
byte[] msg = cm.CipherMsg();
System.out.println("加密后的密文为：" + new String(msg));
// System.out.println("密钥为："+new String(cm.getBinaryKey(key)));

System.out.println(cm.getBinaryKey(key));
System.out.println("解密密文为：" + cm.EncipherMsg(msg, key));

}

}