DES加密实例

最近在学习加密解密的相关知识，为了加强记忆，参照一些资料写了些简单的加解密实现。写不好，欢迎大家拍砖和指教。

 

DES加密实例

package com.royboy.encrypt;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import com.sun.org.apache.xml.internal.security.utils.Base64;

public class DesTester {

	public final static String FILEPATH = "C:\\BitIO.txt";
	public static byte[] data ;

	/**
	 * 生成密钥 
	 * @return 密钥内容
	 * @throws NoSuchAlgorithmException
	 */
	public void generateKey() throws NoSuchAlgorithmException {
		//实例化密钥生成器
		KeyGenerator kg = KeyGenerator.getInstance("DES");
		//初始化
		kg.init(56);
		//生成密钥
		SecretKey secretKey = kg.generateKey();
		//获得二进制编码的密钥
		byte[] b = secretKey.getEncoded();

		/*
		 * 将密钥写入到文件中
		 * */
		File fileInst = new File(FILEPATH);
		try {
			if (!fileInst.exists())
				fileInst.createNewFile();
			FileWriter fw = new FileWriter(fileInst);
			//对生成的密钥进行了BASE64加密
			String keyEncode = Base64.encode(b);
			System.out.println("生成的密钥:"+keyEncode);
			fw.write(keyEncode);
			fw.flush();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException ioe) {
			ioe.printStackTrace();
		}
	}

	private byte[] getKey() {
		byte[] content = null;
		try {
			File fileInst = new File(FILEPATH);
			BufferedInputStream in = new BufferedInputStream(
					new FileInputStream(fileInst));
			ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
			byte[] temp = new byte[1024];
			int size = 0;
			while ((size = in.read(temp)) != -1) {
				out.write(temp, 0, size);
			}
			in.close();
			content = out.toByteArray();
			content = Base64.decode(content);
		} catch(IOException ioe){
			ioe.printStackTrace();
		}catch (Exception e) {
			e.printStackTrace();
		}
		return content;
	}
	
	/**
	 * DES数据加密
	 * @return 加密后的数据(用户base64进行了编码)
	 */
	private String encryptData(){
		byte[] encrypt =null;
		byte[] sk = getKey();
		try {
			//实例化密钥材料
			DESKeySpec dks = new DESKeySpec(sk);
			//实例化秘密密钥工厂
			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
			//生成秘密密钥
			SecretKey secretKey = keyFactory.generateSecret(dks);
			//实例化
			Cipher cipher = Cipher.getInstance("DES");
			//实始化，设置为加密模式
			cipher.init(Cipher.ENCRYPT_MODE, secretKey);
			//执行加密操作
			encrypt = cipher.doFinal(data);
		} catch (Exception e) {
		}
		//对加密后的内容进行了BASE64编码。非必须，对于网络传送数据来说，二进制更为理想
		String encryptStr = Base64.encode(encrypt);
		System.out.println("加密后的数据(base64):"+encryptStr);
		return encryptStr;
	}
	
	/**
	 * DES数据解密
	 * @param d 需要解密的数据
	 * @return 解密后的数据
	 */
	private byte[] decryptData(String encryptStr){
		byte[] decrypt =null;
		/*
		 * 得到密钥材料
		 * */
		byte[] sk = getKey();
		try {
			//实例化密钥材料
			DESKeySpec dks = new DESKeySpec(sk);
			//实例化秘密密钥工厂
			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
			//生成秘密密钥
			SecretKey secretKey = keyFactory.generateSecret(dks);
			//实例化
			Cipher cipher = Cipher.getInstance("DES");
			//实始化，设置为解密模式
			cipher.init(Cipher.DECRYPT_MODE, secretKey);
			//执行解密操作
			decrypt = cipher.doFinal(Base64.decode(encryptStr));
		} catch (Exception e) {
		}
		return decrypt;
	}
	
	/**
	 * DES加密测试方法
	 * @param dataStr 要加密的原始内容
	 * @throws Exception
	 */
	public void desTest(String dataStr) throws Exception{
		System.out.println("=====DES=====");
		System.out.println("原始数据:"+dataStr);
		data = dataStr.getBytes();
		generateKey();
		System.out.println("解密后的数据(string):"+new String(decryptData(encryptData())));
		System.out.println("=====DES=====");
	}
	
	public static void main(String[] args) throws Exception{
		DesTester dt = new DesTester();
		dt.desTest("中华人民共和国");
	}
}