20175212童皓桢实验五网络编程与安全

实验内容

结对编程，完成网络编程与安全相关内容

实验步骤

任务一
任务一要求：

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
实验过程：
由中缀式求得后缀式可以使用栈，伪代码如下：

-   设立一个栈，存放运算符，首先栈为空；
-   从左到右扫描中缀式，若遇到操作数，直接输出，并输出一个空格作为两个操作数的分隔符；
-   若遇到运算符，则与栈顶比较，比栈*别高则进栈，否则退出栈顶元素并输出，然后输出一个空格作分隔符；
-   若遇到左括号，进栈；若遇到右括号，则一直退栈输出，直到退到左括号止。
-   当栈变成空时，输出的结果即为后缀表达式
后缀表达式求值伪代码如下：
-   设置一个操作数栈，开始栈为空；
-   从左到右遍历后缀表达式，遇操作数，进栈；
-   若遇运算符，则从栈中退出两个元素，先退出的放到运算符的右边，后退出的放到运算符左边，运算后的结果再进栈，直到后缀表达式遍历完毕。
-   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表达式的值。

实验代码：

MyDC

public class MyBC {
    private Stack theStack;
    private String input;
    private String output = "";

    public MyBC(String in) {
        input = in;
        int stackSize = input.length();
        theStack = new Stack(stackSize);
    }

    public String doTrans() {
        for (int j = 0; j < input.length(); j++) {
            char ch = input.charAt(j);
            switch (ch) {
                case '+':
                case '-':
                    getOp(ch, 1);
                    break;
                case '*':
                case '/':
                    getOp(ch, 2);
                    break;
                case '(':
                    theStack.push(ch);
                    break;
                case ')':
                    getParen(ch);
                    break;
                default:
                    output = output + ch;
                    break;
            }
        }
        while (!theStack.isEmpty()) {
            output = output + theStack.pop();
        }
        return output;
    }

    public void getOp(char opThis, int prec1) {
        while (!theStack.isEmpty()) {
            char opTop = theStack.pop();
            if (opTop == '(') {
                theStack.push(opTop);
                break;
            } else {
                int prec2;
                if (opTop == '+' || opTop == '-')
                    prec2 = 1;
                else
                    prec2 = 2;
                if (prec2 < prec1) {
                    theStack.push(opTop);
                    break;
                } else
                    output = output + opTop;
            }
        }
        theStack.push(opThis);
    }

    public void getParen(char ch) {
        while (!theStack.isEmpty()) {
            char chx = theStack.pop();
            if (chx == '(')
                break;
            else
                output = output + chx;
        }
    }

    class Stack {
        private int maxSize;
        private char[] stackArray;
        private int top;

        public Stack(int max) {
            maxSize = max;
            stackArray = new char[maxSize];
            top = -1;
        }

        public void push(char j) {
            stackArray[++top] = j;
        }

        public char pop() {
            return stackArray[top--];
        }

        public char peek() {
            return stackArray[top];
        }

        public boolean isEmpty() {
            return (top == -1);
        }
    }
}

MyDC

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;

    public MyDC() {
        stack = new Stack<Integer>();
    }

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

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

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

        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;
    }
}

MyBCTest

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;

    public MyDC() {
        stack = new Stack<Integer>();
    }

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

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

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

        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;
    }
}

运行结果：
20175212童皓桢实验五网络编程与安全

任务二

任务二要求：

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- 提交代码运行截图和码云Git链接

实验过程

java.net.Socket：
套接字是一个网络连接的端点。在java中，使用java.net.Socket对象来表示一个套接字。
要创建一个套接字，可以使用Socket的构造方法，如：public Socket(java.lang.String host, int port)。其中，host是远程机器名或IP地址，port是远程应用程序的端口号。
一旦成功创建了Socket类的一个实例，就可以使用它发送或接收字节流。要发送字节流，必须先调用Socket类的getOutputStream方法来获取一个java.io.OutputStream对象。要向远程应用程序发送文本，通常要从返回的OutputStream对象构建一个java.io.PrintWriter对象。要接收来自连接的另一端的字节流，可以调用Socket类的getInputStream方法，它返回一个java.io.InputStream。
『java.net.ServerSocket』：
ServerSocket是服务器套接字的一个实现。ServerSocket和Socket不同，服务器套接字的角色是，等待来自客户端的连接请求。一旦服务器套接字获得了一个连接请求，它就会创建一个Socket实例，以处理和客户端的通信。
Address

import java.net.*;

public class Address {

    public static void main(String[] args) throws UnknownHostException {

        InetAddress net = InetAddress.getLocalHost();

        System.out.println(net.toString());

    }

}

Client

import java.io.*;
import java.net.*;

public class Client {
    public static void main(String args[]) {
        System.out.println("客户端启动...");
        //while (true) {
        Socket mysocket;
        DataInputStream in = null;
        DataOutputStream out = null;
        try {
            mysocket = new Socket("192.168.56.1", 2019);
            in = new DataInputStream(mysocket.getInputStream());
            out = new DataOutputStream(mysocket.getOutputStream());
            System.out.println("请输入:");
            String str = new BufferedReader(new InputStreamReader(System.in)).readLine();

            MyBC turner = new MyBC(str);
            String infix;
            infix=turner.doTrans();
            StringBuilder newInfix = new StringBuilder(infix.replace(" ",""));
            for (int i = 1; i < infix.length()+(i+1)/2 ; i=i+2) {
                newInfix.insert(i," ");
            }
            out.writeUTF(newInfix.toString());//调用toString()方法,返回newInflx的String值，以便调用writeUTF方法

            String s = in.readUTF();   //in读取信息，堵塞状态
            System.out.println("客户收到服务器的回答:" + s);
            Thread.sleep(500);//在500毫秒数让当前正在执行的线程休眠
        } catch (Exception e) {
            System.out.println("服务器已断开" + e);
        }
        //}
    }
}

Server

import java.io.*;
import java.net.*;

public class Server {
    public static void main(String[] args) throws IOException {
        int answer;
        //while (true) {
        ServerSocket serverForClient = null;
        Socket socketOnServer = null;
        DataOutputStream out = null;
        DataInputStream in = null;
        try {
            serverForClient = new ServerSocket(2019);
        } catch (IOException e1) {
            System.out.println(e1);
        }
        try {
            System.out.println("等待客户呼叫");
            socketOnServer = serverForClient.accept(); //堵塞状态，除非有客户呼叫
            out = new DataOutputStream(socketOnServer.getOutputStream());
            in = new DataInputStream(socketOnServer.getInputStream());
            String s = in.readUTF(); // in读取信息，堵塞状态
            System.out.println("服务器收到客户的提问:" + s);
            MyDC myDC = new MyDC();
            answer = myDC.evaluate(s);
            out.writeUTF(answer + "");
            Thread.sleep(500);
        } catch (Exception e) {
            System.out.println("客户已断开" + e);
        }
        //}
    }
}

运行结果：
20175212童皓桢实验五网络编程与安全

任务三

任务三要求：

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

Client.java

import javax.crypto.Cipher;
import java.io.*;
import java.net.*;
import java.security.Key;

public class Client {
    public static void main(String args[]) {
        System.out.println("客户端启动...");
        //while (true) {
        Socket mysocket;
        DataInputStream in = null;
        DataOutputStream out = null;
        try {
            mysocket = new Socket("192.168.56.1", 2019);
            in = new DataInputStream(mysocket.getInputStream());
            out = new DataOutputStream(mysocket.getOutputStream());
            System.out.println("请输入:");
            String str = new BufferedReader(new InputStreamReader(System.in)).readLine();

            MyBC turner = new MyBC(str);
            String infix;
            infix=turner.doTrans();
            StringBuilder newInfix = new StringBuilder(infix.replace(" ",""));
            for (int i = 1; i < infix.length()+(i+1)/2 ; i=i+2) {
                newInfix.insert(i," ");
            }

            String str1=newInfix.toString();//DES加密
            String a=null;
            FileInputStream f=new FileInputStream("key1.dat");
            ObjectInputStream b=new ObjectInputStream(f);
            Key k=(Key)b.readObject( );
            Cipher cp=Cipher.getInstance("DESede");
            cp.init(Cipher.ENCRYPT_MODE, k);
            byte ptext[]=str1.getBytes("UTF8");
            byte ctext[]=cp.doFinal(ptext);
            for(int i=0;i<ctext.length;i++){
                a+=String.valueOf(ctext[i]);
            }
            FileOutputStream f2=new FileOutputStream("SEnc.dat");
            f2.write(ctext);

            out.writeUTF(a);//调用toString()方法,返回newInflx的String值，以便调用writeUTF方法
            String s = in.readUTF();   //in读取信息，堵塞状态
            System.out.println("客户收到服务器的回答:" + s);
            Thread.sleep(500);//在500毫秒数让当前正在执行的线程休眠
        } catch (Exception e) {
            System.out.println("服务器已断开" + e);
        }
        //}
    }
}

Server.java

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.*;

public class Server {
    public static void main(String[] args) throws IOException {
        int answer;
        //while (true) {
        ServerSocket serverForClient = null;
        Socket socketOnServer = null;
        DataOutputStream out = null;
        DataInputStream in = null;
        try {
            serverForClient = new ServerSocket(2019);
        } catch (IOException e1) {
            System.out.println(e1);
        }
        try {
            System.out.println("等待客户呼叫");
            socketOnServer = serverForClient.accept(); //堵塞状态，除非有客户呼叫
            out = new DataOutputStream(socketOnServer.getOutputStream());
            in = new DataInputStream(socketOnServer.getInputStream());
            String s = in.readUTF(); // in读取信息，堵塞状态

            // 获取密文
            FileInputStream f=new FileInputStream("SEnc.dat");
            int num=f.available();
            byte[ ] ctext=new byte[num];
            f.read(ctext);
            // 获取密钥
            FileInputStream  f2=new FileInputStream("keykb1.dat");
            int num2=f2.available();
            byte[ ] keykb=new byte[num2];
            f2.read(keykb);
            SecretKeySpec k=new  SecretKeySpec(keykb,"DESede");
            // 解密
            Cipher cp=Cipher.getInstance("DESede");
            cp.init(Cipher.DECRYPT_MODE, k);
            byte []ptext=cp.doFinal(ctext);
            // 显示明文
            String p=new String(ptext,"UTF8");

            System.out.println("服务器收到客户的提问:" + p);
            MyDC myDC = new MyDC();
            answer = myDC.evaluate(p);
            out.writeUTF(answer + "");
            Thread.sleep(500);
        } catch (Exception e) {
            System.out.println("客户已断开" + e);
        }
        //}
    }
}

Skey_DES.java

import java.io.*;
import javax.crypto.*;
public class Skey_DES{
    public static void main(String args[])
            throws Exception{
        KeyGenerator kg=KeyGenerator.getInstance("DESede");
        kg.init(168);
        SecretKey k=kg.generateKey( );
        FileOutputStream  f=new FileOutputStream("key1.dat");
        ObjectOutputStream b=new  ObjectOutputStream(f);
        b.writeObject(k);
    }
}

Skey_kb.java

import java.io.*;
import java.security.*;
public class Skey_kb{
    public static void main(String args[]) throws Exception{
        FileInputStream f=new FileInputStream("key1.dat");
        ObjectInputStream b=new ObjectInputStream(f);
        Key k=(Key)b.readObject( );
        byte[ ] kb=k.getEncoded( );
        FileOutputStream  f2=new FileOutputStream("keykb1.dat");
        f2.write(kb);
        // 打印密钥编码中的内容
        for(int i=0;i<kb.length;i++){
            System.out.print(kb[i]+",");
        }
    }
}

运行结果：
20175212童皓桢实验五网络编程与安全

任务四

任务四要求：

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

Client

import java.net.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
public class Client {
    public static void main(String []args) throws Exception
    {
        try
        {
            // 1、创建客户端Socket，指定服务器地址和端口
            Socket socket=new Socket("192.168.56.1",2019);

            System.out.println("客户端成功启动，等待客户端呼叫");
            // 2、获取输出流，向服务器端发送信息
            // 向本机的10001端口发出客户请求
            System.out.println("请输入中缀表达式：");
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            // 由系统标准输入设备构造BufferedReader对象
            PrintWriter write = new PrintWriter(socket.getOutputStream());
            // 由Socket对象得到输出流，并构造PrintWriter对象
            //3、获取输入流，并读取服务器端的响应信息
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            // 由Socket对象得到输入流，并构造相应的BufferedReader对象
            String readline, infix, expression;
            readline = br.readLine(); // 从系统标准输入读入一字符串

            MyBC theTrans = new MyBC(readline);
            infix = theTrans.doTrans();
            StringBuilder newInfix = new StringBuilder(infix.replace(" ",""));
            for (int i = 1; i < infix.length()+(i+1)/2 ; i=i+2) {
                newInfix.insert(i," ");
            }
            System.out.println("后缀表达式： " + newInfix);
            expression=newInfix.toString();

            // 读取对方的DH公钥
            FileInputStream f1=new FileInputStream("Bpub");
            ObjectInputStream b1=new ObjectInputStream(f1);
            PublicKey  pbk=(PublicKey)b1.readObject( );
            //读取自己的DH私钥
            FileInputStream f2=new FileInputStream("Asec");
            ObjectInputStream b2=new ObjectInputStream(f2);
            PrivateKey  prk=(PrivateKey)b2.readObject( );
            // 执行密钥协定
            KeyAgreement ka=KeyAgreement.getInstance("DH");
            ka.init(prk);
            ka.doPhase(pbk,true);
            //生成共享信息
            byte[ ] sb=ka.generateSecret();
            //System.out.println(sb.length);
            byte[]ssb=new byte[24];
            for(int i=0;i<24;i++)
                ssb[i]=sb[i];
            Key k=new SecretKeySpec(ssb,"DESede");
            Cipher cp=Cipher.getInstance("DESede");
            cp.init(Cipher.ENCRYPT_MODE, k);
            byte ptext[]=expression.getBytes("UTF-8");
            byte ctext[]=cp.doFinal(ptext);
            String Str=new String(ctext,"ISO-8859-1");


            while (!readline.equals("end")) {
                // 若从标准输入读入的字符串为 "end"则停止循环
                write.println(Str);
                // 将从系统标准输入读入的字符串输出到Server
                write.flush();
                // 刷新输出流，使Server马上收到该字符串
                System.out.println("加密后的信息:" + Str);
                // 在系统标准输出上打印读入的字符串
                System.out.println("服务器发来的信息:" + in.readLine());
                // 从Server读入一字符串，并打印到标准输出上
                readline = br.readLine(); // 从系统标准输入读入一字符串
            } // 继续循环
            //4、关闭资源
            write.close(); // 关闭Socket输出流
            in.close(); // 关闭Socket输入流
            socket.close(); // 关闭Socket
        }
        catch (Exception e)
        {
            System.out.println(e);//输出异常
        }
        finally
        {

        }

    }
}

Serve

import java.net.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
public class Server{
    public static void main(String []args) throws Exception
    {
        ServerSocket sc = null;
        Socket socket=null;
        try
        {
            MyDC evaluator = new MyDC();

            sc= new ServerSocket(2019);//创建服务器套接字
            //System.out.println("端口号:" + sc.getLocalPort());
            System.out.println("服务器成功启动，等待客户端应答");
            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);
            //使用服务器端RSA的私钥对DES的密钥进行解密
            String aline2=in.readLine();
            System.out.println("客户端发来的信息为："+aline2);


            // 获取密钥
            byte[]ctext=aline2.getBytes("ISO-8859-1");
            // 读取对方的DH公钥
            FileInputStream f1=new FileInputStream("Bpub");
            ObjectInputStream b1=new ObjectInputStream(f1);
            PublicKey  pbk=(PublicKey)b1.readObject( );
            //读取自己的DH私钥
            FileInputStream f2=new FileInputStream("Asec");
            ObjectInputStream b2=new ObjectInputStream(f2);
            PrivateKey  prk=(PrivateKey)b2.readObject( );
            // 执行密钥协定
            KeyAgreement ka=KeyAgreement.getInstance("DH");
            ka.init(prk);
            ka.doPhase(pbk,true);
            //生成共享信息
            byte[ ] sb=ka.generateSecret();
            byte[]ssb=new byte[24];
            for(int i=0;i<24;i++)
                ssb[i]=sb[i];
            SecretKeySpec k=new  SecretKeySpec(ssb,"DESede");

            // 解密
            Cipher cp=Cipher.getInstance("DESede");
            cp.init(Cipher.DECRYPT_MODE, k);
            byte []ptext=cp.doFinal(ctext);
            // 显示明文
            String p=new String(ptext,"UTF8");
            int ans = evaluator.evaluate(p);
            out.println(ans);
            System.out.println("Result = "+ans);

        } catch (Exception e) {
            System.out.println(e);
        }
    }

    //十六进制和十进制转换
    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;
    }
}

KeyAgree

import java.io.*;
import java.math.*;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;

public class KeyAgree{
    public static void main(String args[ ]) throws Exception{
        // 读取对方的DH公钥
        FileInputStream f1=new FileInputStream("Bpub");
        ObjectInputStream b1=new ObjectInputStream(f1);
        PublicKey  pbk=(PublicKey)b1.readObject( );
//读取自己的DH私钥
        FileInputStream f2=new FileInputStream("Asec");
        ObjectInputStream b2=new ObjectInputStream(f2);
        PrivateKey  prk=(PrivateKey)b2.readObject( );
        // 执行密钥协定
        KeyAgreement ka=KeyAgreement.getInstance("DH");
        ka.init(prk);
        ka.doPhase(pbk,true);
        //生成共享信息
        byte[ ] sb=ka.generateSecret();
        for(int i=0;i<sb.length;i++){
            System.out.print(sb[i]+",");
        }
        SecretKeySpec k=new  SecretKeySpec(sb,"DESede");
    }
}

Key_DH.java

import java.io.*;
import java.math.*;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;

import java.io.*;
import java.math.*;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;

public class Key_DH{
    //三个静态变量的定义从
// C:\j2sdk-1_4_0-doc\docs\guide\security\jce\JCERefGuide.html
// 拷贝而来
// The 1024 bit Diffie-Hellman modulus values used by SKIP
    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("Bpub");
        ObjectOutputStream b1=new  ObjectOutputStream(f1);
        b1.writeObject(pbk);
        // 保存私钥
        FileOutputStream  f2=new FileOutputStream("Asec");
        ObjectOutputStream b2=new  ObjectOutputStream(f2);
        b2.writeObject(prk);
    }
}

运行结果：
20175212童皓桢实验五网络编程与安全

任务五

完整性校验结对编程：

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，把后缀表达式用3DES或AES算法加密通过网络把密文和明文的MD5値发送给服务器
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，解密后计算明文的MD5值，和客户端传来的MD5进行比较，一致则调用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
上传测试结果截图和码云链接

Serve

import java.net.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.interfaces.*;
import java.math.*;

public class Server {
    public static void main(String args[]) throws Exception {
        ServerSocket link = null;
        Socket socket = null;
        try {
            link = new ServerSocket(3);// 创建服务器套接字
            //System.out.println("端口号:" + link.getLocalPort());
            System.out.println("等待客户连接");
            socket = link.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);
            // 使用服务器端RSA的私钥对DES的密钥进行解密

            String line = in.readLine();
            BigInteger cipher = new BigInteger(line);
            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();//mod n
            BigInteger m = cipher.modPow(d, n);//m=d (mod n)
            System.out.println("d= " + d);
            System.out.println("n= " + n);
            System.out.println("m= " + m);
            byte[] keykb = m.toByteArray();
            // 使用DES对密文进行解密
            String readline = in.readLine();//读取客户端传送来的数据
            FileInputStream f2 = new FileInputStream("keykb1.dat");
            int num2 = f2.available();
            byte[] ctext = parseHexStr2Byte(readline);
            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");//编码转换
            System.out.println("从客户端接收到信息为：" + p); //打印解密结果
            // 使用Hash函数检测明文完整性
            String aline3 = in.readLine();
            String x = p;
            MessageDigest m2 = MessageDigest.getInstance("MD5");//使用MD5算法返回实现指定摘要算法的 MessageDigest对象
            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("MD5:"+result);
            if (aline3.equals(result)) {
                System.out.println("匹配成功");
            }
            MyDC evaluator = new MyDC();
            int _result = evaluator.value(p);
            out.println(_result);
            out.close();
            in.close();
            link.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }
    //二进制转换成十六进制，防止byte[]数字转换成string类型时造成的数据损失
    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());//将字符串中的小写字母转换成大写字母,然后加在字符串上
        }
        return sb.toString();
    }
    //将十六进制转换为二进制
    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;
    }

}

Client

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 args[]) throws Exception {
        try {
            KeyGenerator kg = KeyGenerator.getInstance("DESede");
            kg.init(168);
            SecretKey k = kg.generateKey();
            byte[] ptext2 = k.getEncoded();
            Socket socket = new Socket("127.0.0.1", 3);
            System.out.println("客户端成功启动，等待客户端呼叫");
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
            BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
            //RSA算法，使用服务器端的公钥对DES的密钥进行加密
            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); // 通过网络将加密后的秘钥传送到服务器
            System.out.println("请输入中缀表达式：");
            //用DES加密明文得到密文
            String s = stdin.readLine(); // 从键盘读入待发送的数据
            String postfix = MyBC.toPostfix(s);
            Cipher cp = Cipher.getInstance("DESede");
            cp.init(Cipher.ENCRYPT_MODE, k);
            byte ptext[] = postfix.getBytes("UTF8");
            byte ctext[] = cp.doFinal(ptext);
            String str = parseByte2HexStr(ctext);
            out.println(str); // 通过网络将密文传送到服务器

            // 将客户端明文的Hash值传送给服务器
            String x = postfix;
            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("MD5:"+result);
            out.println(result);//通过网络将明文的Hash函数值传送到服务器
            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);//输出异常
        } finally {
        }

    }

    //将十六进制转换成二进制
    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();
    }
}

运行结果：
20175212童皓桢实验五网络编程与安全

实验中遇到的问题

问题一：输入表达算式时提示断开连接
20175212童皓桢实验五网络编程与安全
解决办法：输入表达式时一气呵成，而不能像平常一样对已输入的括号内的内容进行修改

参考博客

https://www.cnblogs.com/zxy20175227/p/10923041.html
http://www.cnblogs.com/rocedu/p/6766748.html#SECDSA

结对伙伴及博客链接

20175227

秒客网

20175212童皓桢实验五网络编程与安全

20175212童皓桢实验五网络编程与安全

实验内容

实验步骤

任务一

任务二

任务三

任务四

任务五

实验中遇到的问题

参考博客

结对伙伴及博客链接

相关文章

20175212童皓桢 实验五 网络编程与安全

20175212童皓桢 实验五 网络编程与安全

实验内容

实验步骤

任务一

任务二

任务三

任务四

任务五

实验中遇到的问题

参考博客

结对伙伴及博客链接

相关文章

20175212童皓桢实验五网络编程与安全

20175212童皓桢实验五网络编程与安全