DES加密文件代码,Java代码库,德仔网

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【Java】 DES加密文件
作者:汪超 / 发布于2013/8/20/ 678
只需给定三个参数，一个是密钥的文件地址（代码中有方法生成密钥，保存到文件），一个是需要加密的文件路径，一个是解密后文件放置的路径。简单易用

	package com.gwsi.hbtax.xfaj.util;

	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.security.GeneralSecurityException;

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

	import lantrack.common.config.Config;

	public class FileKey {
	
	
	public String keyFile = (new StringBuilder(Config.EWEBEDIT_UPLOAD_PATH)).append("\\xfaj\\moban\\key.txt").toString();

	public String getKeyFile(){
	 return this.keyFile;
	}
	
	public void setKeyFile(String keyFile){
	 this.keyFile=keyFile;
	}
	
	
	//用java生成一个key并保存到一个二进制文件中去的方法如下：
	public static void saveBytePriveKey(String file) {

	 try {
	 String keyString="de23a211";
	 byte[] keyData=keyString.getBytes();
	 SecretKey key=new SecretKeySpec(keyData,"DES");
	
	
	// KeyGenerator keyGen = KeyGenerator.getInstance("DES");
	//
	// SecretKey key = keyGen.generateKey();// 生成私钥Key

	 FileOutputStream fop = new FileOutputStream(file);
	 fop.write(key.getEncoded());
	 fop.close();
	 } catch (Exception e1) {
	 e1.printStackTrace();
	 }
	 }

	//从密钥文件中读取内容生成密钥
	 public static SecretKey getBytePriveKey(String file) throws Exception {
	 File keyf = new File(file);
	 long length = keyf.length();
	 byte[] bytes = new byte[(int) length];

	 FileInputStream fis = new FileInputStream(keyf);

	 // Read in the bytes
	 int offset = 0;
	 int numRead = 0;

	 while (offset < bytes.length && (numRead = fis.read(bytes, offset, bytes.length - offset)) >= 0) {
	 offset += numRead;
	 }
	 DESKeySpec dks = new DESKeySpec(bytes);
	 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
	 SecretKey key = keyFactory.generateSecret(dks);

	 return key;
	 }

	//文件加密
	public static void encryptFile(String plainFile, String encryptedFile, String keyFile) {
	 try {

	 SecretKey key = getBytePriveKey(keyFile);
	 Cipher cipher = Cipher.getInstance("DES");
	 cipher.init(Cipher.ENCRYPT_MODE, key);

	 FileInputStream fis = new FileInputStream(plainFile);
	 FileOutputStream fos = new FileOutputStream(encryptedFile);
	 crypt(fis, fos, cipher);

	 fis.close();
	 fos.close();

	 } catch (Exception e) {
	 e.printStackTrace();
	 }
	 }

	
	 public static void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException,
	 GeneralSecurityException {
	 int blockSize = cipher.getBlockSize();
	 int outputSize = cipher.getOutputSize(blockSize);
	 System.out.println("blockSize " + blockSize + " outputSize" + outputSize);

	 byte[] inBytes = new byte[blockSize];
	 byte[] outBytes = new byte[outputSize];

	 int inLength = 0;
	 boolean more = true;
	 while (more) {
	 inLength = in.read(inBytes);
	 if (inLength == blockSize) {
	 int outLength = cipher.update(inBytes, 0, blockSize, outBytes);//加密流的解密
	 out.write(outBytes, 0, outLength);
	 } else {
	 more = false;
	 }
	 }
	 if (inLength > 0)
	 outBytes = cipher.doFinal(inBytes, 0, inLength);
	 else
	 outBytes = cipher.doFinal();
	 out.write(outBytes);
	 }


	 //文件解密
	 public static void decryptFile(String encryptedFile, String decryptedFile, String keyFile) {
	 try {

	 SecretKey key = getBytePriveKey(keyFile);
	 Cipher cipher = Cipher.getInstance("DES");
	 cipher.init(Cipher.DECRYPT_MODE, key);
	
	 FileInputStream fis = new FileInputStream(encryptedFile);
	 FileOutputStream fos = new FileOutputStream(decryptedFile);
	 crypt(fis, fos, cipher);

	 fis.close();
	 fos.close();

	 } catch (Exception e) {
	 e.printStackTrace();
	 }

	 }
	
	 public static void main(String[] args) {
	 FileKey fk= new FileKey();
	 String keyFile=fk.getKeyFile();
	 String plainFile="D:\\1.txt";
	 String encryptedFile="D:\\2.txt";
	
	
	 fk.encryptFile(plainFile, encryptedFile, keyFile);
	//解密文件地址
	// String path=
	// (new StringBuilder(Config.EWEBEDIT_UPLOAD_PATH)).append("\\xfaj\\temp\\temp.").append("txt").toString();
	// System.out.println(path);
	// fk.decryptFile(encryptedFile, path, keyFile);
	
	 }
	
	
	
	}
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