java开发网络安全 java开发转网络安全

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mob6454cc769a22 2023-07-02 13:29:37

文章标签 java开发网络安全 java System 客户端 文章分类 Java 后端开发

实验内容

1．掌握Socket程序的编写；

2．掌握密码技术的使用；

3．设计安全传输系统。

实验步骤

1. 基于Java Socket实现安全传输

2. 基于TCP实现客户端和服务器，结对编程一人负责客户端，一人负责服务器

3. 使用Git进行版本控制

4. 选择对称算法进行数据加解密.

5. 选择非对称算法对对称加密密钥进行密钥分发.

6. 选择合适的Hash算法进行完整性验证.

7. 选择合适的算法对Hash值进行签名/验证.

发送方使用DES对明文加密，属于对称加密算法，加密速度快但是初始密钥分发不能保证其安全性，使用RSE加密DES的密钥信息，然后再用对称加密，可以解决密钥分发问题，又能保障加密速度。

接收方接到信息后，使用对称解密算法，用RSA解密密钥信息，首先发送端用Hash函数产生足以区别文件的摘要值，再由接收端使用相同的Hash函数自行产生文件摘要，并比对与先前解密结果是否相符。

实验代码

（客户端）

import java.net.*;
 
import java.io.*;
 
import java.security.*;
 
import javax.crypto.*;
 
import javax.crypto.spec.*;
 
import java.security.spec.*;
 
import javax.crypto.interfaces.*;
 
import java.security.interfaces.*;
 
import java.math.*;
public class Client {
 
    public static void main(String srgs[]) throws Exception {
 
       try {
 
           KeyGenerator kg = KeyGenerator.getInstance("DESede");
 
           kg.init(168);
 
           SecretKey k = kg.generateKey();
 
           byte[] ptext2 = k.getEncoded();
 
 
 
           // 创建连接特定服务器的指定端口的Socket对象
 
           Socket socket = new Socket("192.168.80.1", 8028);
 
           // 网络输入流
 
           BufferedReader in = new BufferedReader(new InputStreamReader(
 
                  socket.getInputStream()));
 
           // 网络输出流
 
           PrintWriter out = new PrintWriter(new BufferedWriter(
 
                  new OutputStreamWriter(socket.getOutputStream())), true);
 
           // 创建键盘输入流
 
           BufferedReader stdin = new BufferedReader(new InputStreamReader(
 
                  System.in));
 
 
 
           FileInputStream f3 = new FileInputStream("Skey_RSA_pub.dat");
 
           ObjectInputStream b2 = new ObjectInputStream(f3);
 
           RSAPublicKey pbk = (RSAPublicKey) b2.readObject();
 
           BigInteger e = pbk.getPublicExponent();
 
           BigInteger n = pbk.getModulus();
 
           BigInteger m = new BigInteger(ptext2);
 
           BigInteger c = m.modPow(e, n);
 
           String cs = c.toString();
 
           out.println(cs); // 通过网络传送到服务器
 
 
 
           System.out.print("请输入待发送的数据：");
 
           String s = stdin.readLine();
 
           Cipher cp = Cipher.getInstance("DESede");
 
           cp.init(Cipher.ENCRYPT_MODE, k);
 
           byte ptext[] = s.getBytes("UTF8");
 
           byte ctext[] = cp.doFinal(ptext);
 
           String str = parseByte2HexStr(ctext);
 
           out.println(str);
 
 
 
           String x = s;
 
           MessageDigest m2 = MessageDigest.getInstance("MD5");
 
           m2.update(x.getBytes());
 
           byte a[] = m2.digest();
 
           String result = "";
 
           for (int i = 0; i < a.length; i++) {
 
              result += Integer.toHexString((0x000000ff & a[i]) | 0xffffff00)
 
                     .substring(6);
 
           }
 
           System.out.println(result);
 
           out.println(result);
 
 
 
           str = in.readLine();// 从网络输入流读取结果
 
           System.out.println("从服务器接收到的结果为：" + str); // 输出服务器返回的结果
 
       } catch (Exception e) {
 
           System.out.println(e);
 
       } finally {
 
       }
 
 
 
    }
 
 
 
    public static String parseByte2HexStr(byte buf[]) {
 
       StringBuffer sb = new StringBuffer();
 
       for (int i = 0; i < buf.length; i++) {
 
           String hex = Integer.toHexString(buf[i] & 0xFF);
 
           if (hex.length() == 1) {
 
              hex = '0' + hex;
 
           }
 
           sb.append(hex.toUpperCase());
 
       }
 
       return sb.toString();
 
    }
 
 
 
    public static byte[] parseHexStr2Byte(String hexStr) {
 
       if (hexStr.length() < 1)
 
           return null;
 
       byte[] result = new byte[hexStr.length() / 2];
 
       for (int i = 0; i < hexStr.length() / 2; i++) {
 
           int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
 
           int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
 
                  16);
 
           result[i] = (byte) (high * 16 + low);
 
       }
 
       return result;
 
    }
 
}
（服务端）
import java.net.*;
 
import java.io.*;
 
import java.security.*;
 
import java.security.spec.*;
 
import javax.crypto.*;
 
import javax.crypto.spec.*;
 
import javax.crypto.interfaces.*;
 
import java.security.interfaces.*;
 
import java.math.*;
 
 
 
public class Server {
 
    public static void main(String srgs[]) throws Exception {
 
       ServerSocket sc = null;
 
       Socket socket = null;
       
       try {
 
           sc = new ServerSocket(8029);// 创建服务器套接字
 
           System.out.println("端口号:" + sc.getLocalPort());
 
           System.out.println("服务器已经启动...");
 
           socket = sc.accept(); // 等待客户端连接
 
           System.out.println("已经建立连接");
 
           // 获得网络输入流对象的引用
 
           BufferedReader in = new BufferedReader(new InputStreamReader(
 
                  socket.getInputStream()));
 
           // //获得网络输出流对象的引用
 
           PrintWriter out = new PrintWriter(new BufferedWriter(
 
                  new OutputStreamWriter(socket.getOutputStream())), true);
 
 
 
           String aline2 = in.readLine();
 
           BigInteger c = new BigInteger(aline2);
 
           FileInputStream f = new FileInputStream("Skey_RSA_priv.dat");
 
           ObjectInputStream b = new ObjectInputStream(f);
 
           RSAPrivateKey prk = (RSAPrivateKey) b.readObject();
 
           BigInteger d = prk.getPrivateExponent();
 
           BigInteger n = prk.getModulus();
 
           BigInteger m = c.modPow(d, n);
 
           byte[] keykb = m.toByteArray();
 
           String aline = in.readLine();// 读取客户端传送来的数据
 
           byte[] ctext = parseHexStr2Byte(aline);
 
           Key k = new SecretKeySpec(keykb, "DESede");
 
           Cipher cp = Cipher.getInstance("DESede");
 
           cp.init(Cipher.DECRYPT_MODE, k);
 
           byte[] ptext = cp.doFinal(ctext);
 
 
 
           String p = new String(ptext, "UTF8");
 
           System.out.println("从客户端接收到信息为：" + p); // 通过网络输出流返回结果给客户端
 
 
 
           String aline3 = in.readLine();
 
           String x = p;
 
           MessageDigest m2 = MessageDigest.getInstance("MD5");
 
           m2.update(x.getBytes());
 
           byte a[] = m2.digest();
 
           String result = "";
 
           for (int i = 0; i < a.length; i++) {
 
              result += Integer.toHexString((0x000000ff & a[i]) | 0xffffff00)
 
                     .substring(6);
 
           }
 
           System.out.println(result);
 
 
 
           if (aline3.equals(result)) {
 
              System.out.println("匹配成功");
 
           }
 
 
 
           out.println("匹配成功");
 
           out.close();
 
           in.close();
 
           sc.close();
 
       } catch (Exception e) {
 
           System.out.println(e);
 
       }
 
    }
 
 
 
    public static String parseByte2HexStr(byte buf[]) {
 
       StringBuffer sb = new StringBuffer();
 
       for (int i = 0; i < buf.length; i++) {
 
           String hex = Integer.toHexString(buf[i] & 0xFF);
 
           if (hex.length() == 1) {
 
              hex = '0' + hex;
 
           }
 
           sb.append(hex.toUpperCase());
 
       }
 
       return sb.toString();
 
    }
 
 
 
    public static byte[] parseHexStr2Byte(String hexStr) {
 
       if (hexStr.length() < 1)
 
           return null;
 
       byte[] result = new byte[hexStr.length() / 2];
 
       for (int i = 0; i < hexStr.length() / 2; i++) {
 
           int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
 
           int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
 
                  16);
 
           result[i] = (byte) (high * 16 + low);
 
       }
 
       return result;
 
    }
 
}

java开发网络安全 java开发转网络安全_客户端