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：

1. 结对实现中缀表达式转后缀表达式的功能 MyBC.java
2. 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，比栈顶级别高则进栈，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;elseprec2 = 2;if (prec2 < prec1) {theStack.push(opTop);break;} elseoutput = output + opTop;}}theStack.push(opThis);}public void getParen(char ch) {while (!theStack.isEmpty()) {char chx = theStack.pop();if (chx == '(')break;elseoutput = 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isOperatorif (isOperator(token)) {//从栈中弹出操作数2op2 = stack.pop();//从栈中弹出操作数1op1 = 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isOperatorif (isOperator(token)) {//从栈中弹出操作数2op2 = stack.pop();//从栈中弹出操作数1op1 = 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：

任务二

任务二要求：

1人负责客户端，一人负责服务器

1. 注意责任归宿，要会通过测试证明自己没有问题
2. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
3. 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
4. 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
5. 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：

任务三

任务三要求：

1人负责客户端，一人负责服务器

1. 注意责任归宿，要会通过测试证明自己没有问题
2. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
3. 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
4. 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
5. 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：

任务四

任务四要求：

1人负责客户端，一人负责服务器

1. 注意责任归宿，要会通过测试证明自己没有问题
2. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
3. 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
4. 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
5. 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
6. 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Serverwrite.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 SKIPprivate 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 modulusprivate static final BigInteger skip1024Modulus= new BigInteger(1, skip1024ModulusBytes);// The base used with the SKIP 1024 bit modulusprivate 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：

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

1. 注意责任归宿，要会通过测试证明自己没有问题
2. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
3. 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
4. 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
5. 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
6. 客户端显示服务器发送过来的结果
7. 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 nBigInteger 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：

实验中遇到的问题

问题一：输入表达算式时提示断开连接

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