2017-2018-2 20165218 实验五《网络编程与安全》实验报告

实验五《网络编程与安全》实验报告

课程：java程序设计

姓名：赵冰雨

学号：20165218

指导教师：娄嘉鹏

实验日期：2018.5.29

实验内容、步骤与体会：

任务一

结对实现中缀表达式转后缀表达式的功能 MyBC.java
结对实现从上面功能中获取的表达式中实现后缀表达式求值的功能,调用MyDC.java

中缀转后缀

设置一个运算符栈，一个后缀表达式字符串
从左到右一次对中缀表达式中的每个字符进行如下处理：
- 若ch是左括号(，入栈
- 如果ch是数字，将其后数字添加到后缀表达式字符串之后，并添加空格
- 如果ch是运算符，将栈顶若干优先级高于ch的运算符出栈，添加到后缀表达式字符串之后，再将ch入栈。当(运算符在栈中时，它的优先级最低
- 若ch是)，则若干运算符全部出栈，直到出栈的是左括号，一对括号匹配
若表达式结束，将栈中运算符全部出栈，添加到后缀表达式字符串之后

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.lang.String;
import org.junit.Test;

public class MyBC{
    private static final Map<Character, Integer> basic = new HashMap<Character, Integer>();
    static {
        basic.put('-', 1);
        basic.put('+', 1);
        basic.put('*', 2);
        basic.put('/', 2);
        basic.put('(', 0);
    }

    /**
     * 将  中缀表达式  转化为  后缀表达式
     */
    public static String toSuffix(String infix){
        List<String> queue = new ArrayList<String>();
        List<Character> stack = new ArrayList<Character>();

        char[] charArr = infix.trim().toCharArray();
        String standard = "*/+-()";
        char ch = '&';
        int len = 0;
        for (int i = 0; i < charArr.length; i++) {

            ch = charArr[i];
            if(Character.isDigit(ch)) {
                len++;
            }else if(Character.isLetter(ch)) {
                len++;
            }else if(ch == '.'){
                len++;
            }else if(Character.isSpaceChar(ch)) {
                if(len > 0) {
                    queue.add(String.valueOf(Arrays.copyOfRange(charArr, i - len, i)));
                    len = 0;
                }
                continue;
            }else if(standard.indexOf(ch) != -1) {
                if(len > 0) {
                    queue.add(String.valueOf(Arrays.copyOfRange(charArr, i - len, i)));
                    len = 0;
                }
                if(ch == '(') {
                    stack.add(ch);
                    continue;
                }
                if (!stack.isEmpty()) {
                    int size = stack.size() - 1;
                    boolean flag = false;
                    while (size >= 0 && ch == ')' && stack.get(size) != '(') {
                        queue.add(String.valueOf(stack.remove(size)));
                        size--;
                        flag = true;
                    }
                    while (size >= 0 && !flag && basic.get(stack.get(size)) >= basic.get(ch)) {
                        queue.add(String.valueOf(stack.remove(size)));
                        size--;
                    }
                }
                if(ch != ')') {
                    stack.add(ch);
                } else {
                    stack.remove(stack.size() - 1);
                }
            }
            if(i == charArr.length - 1) {
                if(len > 0) {
                    queue.add(String.valueOf(Arrays.copyOfRange(charArr, i - len+1, i+1)));
                }
                int size = stack.size() - 1;
                while (size >= 0) {
                    queue.add(String.valueOf(stack.remove(size)));
                    size--;
                }
            }
        }
        return queue.stream().collect(Collectors.joining(" "));
    }
}

后缀表达式求值

设置一个操作数栈，从左向右依次对后缀表达式字符串中的每个字符ch进行处理
若ch是数字，先将其后连续若干数字转化为整数，再将该整数入栈；
若ch是运算符，出栈两个值进行运算，运算结果再入栈；
重复以上步骤，直至后缀表达式结束，栈中最后一个数字就是所求表达式的值

import java.util.StringTokenizer;
import java.util.Stack;
public class MyDC {
    /**
     * constant for addition symbol
     */
    private final char ADD = '+';
    /**
     * constant for subtraction symbol
     */
    private final char SUBTRACT = '-';
    /**
     * constant for multiplication symbol
     */
    private final char MULTIPLY = '*';
    /**
     * constant for division symbol
     */
    private final char DIVIDE = '/';
    /**
     * the stack
     */
    private Stack<Integer> stack;

    /**
     * Sets up this evalutor by creating a new stack.
     */
    public MyDC() {
        stack = new Stack<Integer>();
    }

    public int evaluate(String expr) {
        int op1, op2, result = 0;
        String token;
        StringTokenizer tokenizer = new StringTokenizer(expr);

        while (tokenizer.hasMoreTokens()) {
            token = tokenizer.nextToken();

            if (isOperator(token)) {  //如果是运算符，调用isOperator
                op2 = (stack.pop()).intValue(); //从栈中弹出操作数2
                op1 = (stack.pop()).intValue();//从栈中弹出操作数1
                result = evalSingleOp(token.charAt(0), op1, op2);
                //根据运算符和两个操作数调用evalSingleOp计算result;
                stack.push(new Integer(result)); //计算result入栈;
            } else//如果是操作数

                stack.push(new Integer(Integer.parseInt(token)));        //操作数入栈;
        }

        return result;
    }

    private boolean isOperator(String token) {
        return (token.equals("+") || token.equals("-") ||
                token.equals("*") || token.equals("/"));
    }

    private int evalSingleOp(char operation, int op1, int op2) {
        int result = 0;

        switch (operation) {
            case ADD:
                result = op1 + op2;
                break;
            case SUBTRACT:
                result = op1 - op2;
                break;
            case MULTIPLY:
                result = op1 * op2;
                break;
            case DIVIDE:
                result = op1 / op2;
        }

        return result;
    }
}

任务二

1人负责客户端，一人负责服务器
注意责任归宿，要会通过测试证明自己没有问题
基于Java Socket实现客户端/服务器功能，传输方式用TCP
客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式通过网络发送给服务器
服务器接收到后缀表达式，调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
客户端显示服务器发送过来的结果

服务器代码

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Service {
    public static void main(String[] args) throws IOException{
        Service socketService = new Service();
        socketService.oneServer();
    }
    public  void oneServer(){
        try{
            ServerSocket server=null;
            try{
                server=new ServerSocket(5218);
                System.out.println("服务器启动成功！");
            }catch(Exception e) {
                System.out.println("没有启动监听！"+e);
            }
            Socket socket=null;
            try{
                socket=server.accept();
            }catch(Exception e) {
                System.out.println("Error."+e);
            }
            String line,line2;
            BufferedReader in=new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter writer=new PrintWriter(socket.getOutputStream());
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            line2=in.readLine();
            System.out.println("客户端:"+line2);
            MyDC f = new MyDC();
            System.out.printf("%d",f.evaluate(line2));
            writer.println(Integer.toString(f.evaluate(line2)));
            line=br.readLine();
            while(!line.equals("end")){
                writer.println(line);
                writer.flush();
                System.out.println("服务器:"+Integer.toString(f.evaluate(in.readLine())));
                System.out.println("客户端:"+in.readLine());
                line=br.readLine();
            }
            writer.close();
            in.close();
            socket.close();
            server.close();
        }catch(Exception e) {
            System.out.println("Error."+e);
        }
    }
}

客户端代码

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.URL;

public class Client {
    public static void main(String[] args) throws IOException {
        try {
            //Socket socket = new Socket("172.20.10.6", 5218);
            Socket socket = new Socket("172.20.10.6", 5218);
            System.out.println("客户端启动成功！");
            System.out.println("请输入中缀表达式：");
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            PrintWriter write = new PrintWriter(socket.getOutputStream());
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            String expression;

            MyBC bc = new MyBC();
            expression = br.readLine();
            String input =new String();
            input = bc.toSuffix("20-16/4+52-18*2");
                                //学号是：20165218（20）-（16）/4+（53）-（1）*2
            while (!expression.equals("end")) {
                write.println(input);
                write.println(expression);
                write.flush();
                System.out.println("转化的后缀表达式为:" + input);
                System.out.println("服务器返回值为:" + in.readLine());
                expression = br.readLine();
            }
            write.close();
            in.close();
            socket.close();
        } catch (Exception e) {
            System.out.println("无法监听:" + e);
        }
    }
}

任务三

加密结对编程：1人负责客户端，一人负责服务器
0. 注意责任归宿，要会通过测试证明自己没有问题

基于Java Socket实现客户端/服务器功能，传输方式用TCP

客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密后通过网络把密文发送给服务器

服务器接收到后缀表达式表达式后，进行解密（和客户端协商密钥，可以用数组保存），然后调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端

客户端显示服务器发送过来的结果

AES算法代码

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class AesEncodeUtil {

    //初始向量
    public static final String VIPARA = "aabbccddeeffgghh";   //AES 为16bytes. DES 为8bytes

    //编码方式
    public static final String bm = "UTF-8";

    //私钥
    private static final String ASE_KEY = "aabbccddeeffgghh";   //AES固定格式为128/192/256 bits.即：16/24/32bytes。DES固定格式为128bits，即8bytes。

    /**
     * 加密
     *
     * @param cleartext
     * @return
     */
    public static String encrypt(String cleartext) {
        //加密方式： AES128(CBC/PKCS5Padding) + Base64, 私钥：aabbccddeeffgghh
        try {
            IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
            //两个参数，第一个为私钥字节数组， 第二个为加密方式 AES或者DES
            SecretKeySpec key = new SecretKeySpec(ASE_KEY.getBytes(), "AES");
            //实例化加密类，参数为加密方式，要写全
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); //PKCS5Padding比PKCS7Padding效率高，PKCS7Padding可支持IOS加解密
            //初始化，此方法可以采用三种方式，按加密算法要求来添加。（1）无第三个参数（2）第三个参数为SecureRandom random = new SecureRandom();中random对象，随机数。(AES不可采用这种方法)（3）采用此代码中的IVParameterSpec
            cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
            //加密操作,返回加密后的字节数组，然后需要编码。主要编解码方式有Base64, HEX, UUE,7bit等等。此处看服务器需要什么编码方式
            byte[] encryptedData = cipher.doFinal(cleartext.getBytes(bm));

            return new BASE64Encoder().encode(encryptedData);
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }
    }

    /**
     * 解密
     *
     * @param encrypted
     * @return
     */
    public static String decrypt(String encrypted) {
        try {
            byte[] byteMi = new BASE64Decoder().decodeBuffer(encrypted);
            IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
            SecretKeySpec key = new SecretKeySpec(
                    ASE_KEY.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            //与加密时不同MODE:Cipher.DECRYPT_MODE
            cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);
            byte[] decryptedData = cipher.doFinal(byteMi);
            return new String(decryptedData, bm);
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }
    }
}

服务器代码

import java.awt.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class ServiceAes {
    public static void main(String[] args) throws IOException{
        Service socketService = new Service();
        socketService.oneServer();
    }
    public  void oneServer(){
        try{
            ServerSocket server=null;
            try{
                server=new ServerSocket(5223);
                System.out.println("服务器启动成功！");
            }catch(Exception e) {
                System.out.println("没有启动监听！"+e);
            }
            Socket socket=null;
            try{
                socket=server.accept();
            }catch(Exception e) {
                System.out.println("Error."+e);
            }
            String line,line2;
            BufferedReader in=new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter writer=new PrintWriter(socket.getOutputStream());
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            line2=in.readLine();
            System.out.println("客户端:"+line2);

            //创建对象aes，并调用 AesEncodeUtil 类中的解密方法
            AesEncodeUtil aes = new AesEncodeUtil();
            String line3 = new String();
            line3 = aes.decrypt(line2);
            //调用 MyDC 类计算值
            MyDC f = new MyDC();
            System.out.printf("%d",f.evaluate(line3));
            writer.println(Integer.toString(f.evaluate(line3)));
            line=br.readLine();
            while(!line.equals("end")){
                writer.println(line);
                writer.flush();
                System.out.println("客户端:"+in.readLine());
                System.out.println("服务器:"+Integer.toString(f.evaluate(in.readLine())));
                line=br.readLine();
            }
            writer.close();
            in.close();
            socket.close();
            server.close();
        }catch(Exception e) {
            System.out.println("Error."+e);
        }
    }
}

客户端代码

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.URL;

public class ClientAes {
    public static void main(String[] args) throws IOException {
        try {
            //Socket socket = new Socket("10.1.1.234", 5218);
            //Socket socket = new Socket("10.1.1.230", 5223);
            Socket socket = new Socket("172.20.10.2", 5223);
            System.out.println("客户端启动成功！");
            System.out.println("请输入中缀表达式：");
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            PrintWriter write = new PrintWriter(socket.getOutputStream());
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            String expression;

            MyBC bc = new MyBC();
            expression = br.readLine();
            String input =new String();
            String input2 = new String();

            input = bc.toSuffix("1+(4*2)/2+5+4*3-4");
            AesEncodeUtil aes = new AesEncodeUtil();
            input2 = aes.encrypt(input);
            //创建对象aes，并调用 AesEncodeUtil 类中的加密方法
            while (!expression.equals("end")) {
                write.println(input2);
                write.println(expression);
                write.flush();
                System.out.println("aes加密的后缀表达式为:" );
                System.out.println("服务器返回值为:" + in.readLine());
                expression = br.readLine();
            }
            write.close();
            in.close();
            socket.close();
        } catch (Exception e) {
            System.out.println("无法监听:" + e);
        }
    }
}

任务四

密钥分发结对编程：1人负责客户端，一人负责服务器
0. 注意责任归宿，要会通过测试证明自己没有问题

基于Java Socket实现客户端/服务器功能，传输方式用TCP

客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密通过网络把密文发送给服务器

客户端和服务器用DH算法进行3DES或AES算法的密钥交换

服务器接收到后缀表达式表达式后，进行解密，然后调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端

客户端显示服务器发送过来的结果

执行Diffie-Hellman算法
- 创建DH公钥和私钥
- 创建共享密钥
创建DH公钥和私钥

public class Key_DH{
    private static final byte skip1024ModulusBytes[] = {
            (byte)0xF4, (byte)0x88, (byte)0xFD, (byte)0x58,
            (byte)0x4E, (byte)0x49, (byte)0xDB, (byte)0xCD,
            (byte)0x20, (byte)0xB4, (byte)0x9D, (byte)0xE4,
            (byte)0x91, (byte)0x07, (byte)0x36, (byte)0x6B,
            (byte)0x33, (byte)0x6C, (byte)0x38, (byte)0x0D,
            (byte)0x45, (byte)0x1D, (byte)0x0F, (byte)0x7C,
            (byte)0x88, (byte)0xB3, (byte)0x1C, (byte)0x7C,
            (byte)0x5B, (byte)0x2D, (byte)0x8E, (byte)0xF6,
            (byte)0xF3, (byte)0xC9, (byte)0x23, (byte)0xC0,
            (byte)0x43, (byte)0xF0, (byte)0xA5, (byte)0x5B,
            (byte)0x18, (byte)0x8D, (byte)0x8E, (byte)0xBB,
            (byte)0x55, (byte)0x8C, (byte)0xB8, (byte)0x5D,
            (byte)0x38, (byte)0xD3, (byte)0x34, (byte)0xFD,
            (byte)0x7C, (byte)0x17, (byte)0x57, (byte)0x43,
            (byte)0xA3, (byte)0x1D, (byte)0x18, (byte)0x6C,
            (byte)0xDE, (byte)0x33, (byte)0x21, (byte)0x2C,
            (byte)0xB5, (byte)0x2A, (byte)0xFF, (byte)0x3C,
            (byte)0xE1, (byte)0xB1, (byte)0x29, (byte)0x40,
            (byte)0x18, (byte)0x11, (byte)0x8D, (byte)0x7C,
            (byte)0x84, (byte)0xA7, (byte)0x0A, (byte)0x72,
            (byte)0xD6, (byte)0x86, (byte)0xC4, (byte)0x03,
            (byte)0x19, (byte)0xC8, (byte)0x07, (byte)0x29,
            (byte)0x7A, (byte)0xCA, (byte)0x95, (byte)0x0C,
            (byte)0xD9, (byte)0x96, (byte)0x9F, (byte)0xAB,
            (byte)0xD0, (byte)0x0A, (byte)0x50, (byte)0x9B,
            (byte)0x02, (byte)0x46, (byte)0xD3, (byte)0x08,
            (byte)0x3D, (byte)0x66, (byte)0xA4, (byte)0x5D,
            (byte)0x41, (byte)0x9F, (byte)0x9C, (byte)0x7C,
            (byte)0xBD, (byte)0x89, (byte)0x4B, (byte)0x22,
            (byte)0x19, (byte)0x26, (byte)0xBA, (byte)0xAB,
            (byte)0xA2, (byte)0x5E, (byte)0xC3, (byte)0x55,
            (byte)0xE9, (byte)0x2F, (byte)0x78, (byte)0xC7
    };
    // The SKIP 1024 bit modulus
    private static final BigInteger skip1024Modulus
            = new BigInteger(1, skip1024ModulusBytes);
    // The base used with the SKIP 1024 bit modulus
    private static final BigInteger skip1024Base = BigInteger.valueOf(2);
    public static void main(String args[ ]) throws Exception{
        DHParameterSpec DHP=
                new DHParameterSpec(skip1024Modulus,skip1024Base);

        KeyPairGenerator kpg= KeyPairGenerator.getInstance("DH");
        kpg.initialize(DHP);
        KeyPair kp=kpg.genKeyPair();

        PublicKey pbk=kp.getPublic();
        PrivateKey prk=kp.getPrivate();
        // 保存公钥
        FileOutputStream  f1=new FileOutputStream(args[0]);
        ObjectOutputStream b1=new  ObjectOutputStream(f1);
        b1.writeObject(pbk);
        // 保存私钥
        FileOutputStream  f2=new FileOutputStream(args[1]);
        ObjectOutputStream b2=new  ObjectOutputStream(f2);
        b2.writeObject(prk);
    }
}

代码托管地址

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原文地址：https://www.cnblogs.com/zicerain/p/9131053.html