2018-2019-20175225 实验五《网络编程与安全》实验报告
实验步骤
任务一
- 两人一组结对编程
- 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
-
将运算符写在两个操作数中间的表达式,称为“中缀表达式”,如1+2*(3-4)+5。在中缀表达式中,运算符具有不同的优先级,圆括号用于改变运算符的运算次序,所以求值过程不能直接按照从左到右的顺序进行。
-
将运算符写在两个操作数之后的表达式称为“后缀表达式”,如上面的中缀表达式可转换为后缀表达式1 2 3 4 - * + 5 +。后缀表达式中没有括号,而且运算符没有优先级。后缀表达式的求值过程能够严格地从左到右按顺序进行,符合运算器的求值规律。
-
表达式求值算法分两步进行:①中缀转后缀;②求后缀表达式的值。
-
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。
实验主要代码
- 中缀转后缀
package shiyan5;
import java.util.Stack;
public class MyBC{
String jieguo = "";
public MyBC (String[] args) {
Stack<String> z = new Stack<String>();
String t = "";
for (int i = 0; i < args.length; i++) {
switch (args[i]) {
case "(":
z.push(args[i]);
break;
case "+":
case "-":
while(z.empty() != true) {
t = z.pop();
if (t.equals("(")) {
z.push(t);
break;
}
jieguo = jieguo + t + " ";
}
z.push(args[i]);
break;
case "*":
case "/":
while(z.empty() != true) {
t = z.pop();
if (t.equals("+") || t.equals("-") || t.equals("(")) {
z.push(t);
break;
}
jieguo = jieguo + t + " ";
}
z.push(args[i]);
break;
case ")":
while (z.empty()== false) {
t = z.pop();
if (t.equals("(")) {
break;
} else {
jieguo = jieguo + t + " ";
}
}
break;
case" ":
break;
default:
jieguo = jieguo + args[i] + " ";
break;
}
}
while (z.empty() == false) {
jieguo = jieguo + z.pop() + " ";
}
System.out.println(jieguo);
}
}
实验结果
任务二
- 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
实验过程
- 通过终端中输入ipconfig 或者使用InetAddress类的静态方法getLocalHost()获得一个InetAddress的对象获取服务器端IP地址
- 客户端通过命令行输入待连接的服务器的IP地址
- 调用InetAddress类中的geetByName方法获取输入的IP地址;
- 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。
- 方法getInputStream() 获得一个输入流
- 方法getOutputStream() 获得一个输出流
- 服务器端调用ServerSocket实现套接字
- 使用accept() 方法连接客户端和服务器的套接字
- 方法getInputStream() 获得一个输入流
- 方法getOutputStream() 获得一个输出流
实验代码
- 获取本机的地址
package shiyan5;
import java.net.*;
public class getHostAddress {
public static void main(String[] args) {
try{
InetAddress hostaddress = InetAddress.getLocalHost();
System.out.println(hostaddress.toString());
}catch (UnknownHostException e){
System.out.println(e);
}
}
}
- 客户端
package 实验五;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.Socket;
import java.util.Scanner;
public class Client {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
System.out.println("请输入中缀表达式:");
String infix = inn.nextLine();
String [] str = infix.split(" ");
System.out.println("已传递后缀表达式");
MyBC suffix =new MyBC(str);
out.writeUTF(suffix.jieguo);
String result = in.readUTF();
System.out.println("已收到计算结果"+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接"+e);
}
}
}
- 服务器端
package 实验五;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public class Sever {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("双方已断开连接"+e);
}
try{
System.out.println("准备接受对方传来的问题");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
String suffix = in.readUTF();
String [] str = suffix.split(" ");
System.out.println("收到问题,正在解决:"+suffix);
System.out.println("已传输得出结果:");
MyDC myDC = new MyDC(str);
String answer = String.valueOf(myDC.answer);
out.writeUTF(answer+"");
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接");
}
}
}
实验结果
- 客户端
- 服务器端
任务三
- 加密结对编程: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DES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
实验过程
- 实现DES加密主要有以下几个步骤:
- 对称密钥的生成和保存;
- 使用对称密钥进行加密和解密;
- 从文件中获取加密时使用的密钥,使用密钥进行解密;
- 生成密钥文件
实验代码
- 客户端
package 实验五;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.Socket;
import java.util.Scanner;
public class Client1{
public static void main(String[] args) {
Scanner inn = new Scanner(System.in);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
KeyGenerator kg = KeyGenerator.getInstance("DESede");
kg.init(168);
SecretKey k = kg.generateKey();
byte []kb = k.getEncoded();
out.writeUTF(kb.length+ "");
System.out.println("产生的密钥为");
for(int i=0;i<kb.length;i++) {
System.out.print(kb[i]+ " ");
out.writeUTF(kb[i] +"");
}
System.out.println("\n请输入中缀表达式:");
String infix = inn.nextLine();
String [] str = infix.split(" ");
System.out.println("后缀表达式为");
MyBC suffix =new MyBC(str);
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.ENCRYPT_MODE,k);
byte ptext[] = suffix.jieguo.getBytes("UTF8");
byte ctext[] = cp.doFinal(ptext);
out.writeUTF(ctext.length + "");
for(int i=0;i<ctext.length;i++) {
out.writeUTF(ctext[i] +"");
}
String result = in.readUTF();
System.out.println("已收到计算结果"+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接"+e);
}
}
}
- 服务器端
package 实验五;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public class Sever1{
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("双方已断开连接"+e);
}
try{
System.out.println("准备接受对方传来的问题");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
String keylength = in.readUTF();
byte []kb = new byte[Integer.parseInt(keylength)];
System.out.println("收到的密钥为:");
for(int i = 0;i<Integer.parseInt(keylength);i++) {
String str = in.readUTF();
kb[i] = Byte.parseByte(str);
System.out.print(kb[i] + " ");
}
SecretKeySpec k = new SecretKeySpec(kb, "DESede");
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.DECRYPT_MODE, k);
String clength = in.readUTF();
byte ctext[] = new byte[Integer.parseInt(clength)];
for (int i = 0;i<Integer.parseInt(clength);i++) {
String temp = in.readUTF();
ctext[i] = Byte.parseByte(temp);
}
byte[] ptext = cp.doFinal(ctext);
String suffix = new String(ptext,"UTF8");
String [] str = suffix.split(" ");
System.out.println("\n收到问题,解密后的后缀表达式为:"+suffix);
System.out.println("已传输得出结果:");
MyDC myDC = new MyDC(str);
String answer = String.valueOf(myDC.answer);
out.writeUTF(answer+"");
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接");
}
}
}
实验结果
-
客户端
-
服务器端
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
- 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DES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DES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
实验过程
- 两人先使用Key_DH类生成各自的DH公钥和私钥
- 俩人使用对方的公钥和自己的私钥,用KeyAgree,生成共享密钥
- 客户端使用共享密钥对原有的密钥进行加密,并把密文和加密后的密钥传输给服务器
- 服务器先用共享密钥对客户端加密的密钥进行解密,再用解密后的密钥解密密文
实验代码
- 客户端
package 实验五;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.security.*;
import java.util.Scanner;
import java.net.*;
public class Client2 {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in
);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
Key_DH.DH ("Lpub.dat","Lpri.dat");
FileInputStream my = new FileInputStream("Lpub.dat");
ObjectInputStream mypub = new ObjectInputStream(my);
Key kp = (Key) mypub.readObject();
ByteArrayOutputStream DH = new ByteArrayOutputStream();
ObjectOutputStream myDH = new ObjectOutputStream(DH);
myDH.writeObject(kp);
byte []pub = DH.toByteArray();
out.writeUTF(pub.length+"");
for(int i=0;i<pub.length;i++) {
out.writeUTF(pub[i]+ "");
}
Thread.sleep(1000);
int length = Integer.parseInt(in.readUTF());
byte cpub[] = new byte[length];
for(int i=0;i<length;i++) {
String temp = in.readUTF();
cpub[i] = Byte.parseByte(temp);
}
ByteArrayInputStream ckey1 = new ByteArrayInputStream(cpub);
ObjectInputStream ckey = new ObjectInputStream(ckey1);
Key k = (Key) ckey.readObject();
FileOutputStream f2 = new FileOutputStream("W1pub.dat");
ObjectOutputStream b2 = new ObjectOutputStream(f2);
b2.writeObject(k);
KeyAgree.Agree("W1pub.dat","Lpri.dat");
FileInputStream f = new FileInputStream("sb.dat");
byte[] keysb = new byte[24];
f.read(keysb);
System.out.println("公共密钥为:");
for (int i = 0;i<24;i++) {
System.out.print(keysb[i]+" ");
}
System.out.println("\n请输入中缀表达式:");
String infix = inn.nextLine();
String [] str = infix.split(" ");
System.out.println("已传递后缀表达式");
MyBC suffix =new MyBC(str);
SecretKeySpec k1 = new SecretKeySpec(keysb, "DESede");
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.ENCRYPT_MODE, k1);
byte ptext[] = suffix.jieguo.getBytes("UTF8");
byte ctext[] = cp.doFinal(ptext);
System.out.println("加密后的后缀表达式为:");
for (int i = 0; i < ctext.length; i++) {
System.out.print(ctext[i] + " ");
}
out.writeUTF(ctext.length + "");
for (int i = 0; i < ctext.length; i++) {
out.writeUTF(ctext[i] + "");
}
String result = in.readUTF();
System.out.println("\n已收到计算结果"+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接"+e);
}
}
}
- 服务器端
package 实验五;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.Key;
public class Sever2{
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("双方已断开连接"+e);
}
try{
System.out.println("准备接受对方传来的问题");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
Key_DH.DH("Wpub.dat","Wpri.dat");
int length = Integer.parseInt(in.readUTF());
byte cpub[] = new byte[length];
for(int i=0;i<length;i++) {
String temp = in.readUTF();
cpub[i] = Byte.parseByte(temp);
}
ByteArrayInputStream ckey1 = new ByteArrayInputStream(cpub);
ObjectInputStream ckey = new ObjectInputStream(ckey1);
Key k1 = (Key) ckey.readObject();
FileOutputStream f2 = new FileOutputStream("Lpub.dat");
ObjectOutputStream b2 = new ObjectOutputStream(f2);
b2.writeObject(k1);
FileInputStream my = new FileInputStream("Wpub.dat");
ObjectInputStream mypub = new ObjectInputStream(my);
Key kp = (Key) mypub.readObject();
ByteArrayOutputStream DH = new ByteArrayOutputStream();
ObjectOutputStream myDH = new ObjectOutputStream(DH);
myDH.writeObject(kp);
byte []pub = DH.toByteArray();
out.writeUTF(pub.length+"");
for(int i=0;i<pub.length;i++) {
out.writeUTF(pub[i]+ "");
}
KeyAgree.Agree("Lpub.dat","Wpri.dat");
FileInputStream f = new FileInputStream("sb.dat");
byte[] keysb = new byte[24];
f.read(keysb);
System.out.println("公共密钥为:");
for (int i = 0;i<24;i++) {
System.out.print(keysb[i]+" ");
}
SecretKeySpec k = new SecretKeySpec(keysb, "DESede");
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.DECRYPT_MODE, k);
String clength = in.readUTF();
byte ctext[] = new byte[Integer.parseInt(clength)];
for (int i = 0; i < Integer.parseInt(clength); i++) {
String temp = in.readUTF();
ctext[i] = Byte.parseByte(temp);
}
byte[] ptext = cp.doFinal(ctext);
String suffix = new String(ptext, "UTF8");
String [] str = suffix.split(" ");
System.out.println("\n收到问题,正在解密后缀表达式:"+suffix);
System.out.println("已传输得出结果:");
MyDC myDC = new MyDC(str);
String answer = String.valueOf(myDC.answer);
out.writeUTF(answer+"");
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接");
}
}
}
- KeyAgree
package 实验五;
import javax.crypto.KeyAgreement;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.security.PrivateKey;
import java.security.PublicKey;
public class KeyAgree {
public static void Agree(String str1,String str2) throws Exception{
// 读取对方的DH公钥
FileInputStream f1=new FileInputStream(str1);
ObjectInputStream b1=new ObjectInputStream(f1);
PublicKey pbk=(PublicKey)b1.readObject( );
//读取自己的DH私钥
FileInputStream f2=new FileInputStream(str2);
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();
FileOutputStream fsb = new FileOutputStream("sb.dat");
fsb.write(sb);
}
}
- Key_DH
package 实验五;
import javax.crypto.spec.DHParameterSpec;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
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 DH(String str1,String str2) 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(str1);
ObjectOutputStream b1=new ObjectOutputStream(f1);
b1.writeObject(pbk);
// 保存私钥
FileOutputStream f2=new FileOutputStream(str2);
ObjectOutputStream b2=new ObjectOutputStream(f2);
b2.writeObject(prk);
}
}
实验结果
-
客户端
-
服务器端
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
实验代码
- 客户端
package 实验五;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.Socket;
import java.security.Key;
import java.util.Scanner;
public class Client3 {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in
);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
Key_DH.DH("Lpub.dat","Lpri.dat");
FileInputStream my = new FileInputStream("Lpub.dat");
ObjectInputStream mypub = new ObjectInputStream(my);
Key kp = (Key) mypub.readObject();
ByteArrayOutputStream DH = new ByteArrayOutputStream();
ObjectOutputStream myDH = new ObjectOutputStream(DH);
myDH.writeObject(kp);
byte []pub = DH.toByteArray();
out.writeUTF(pub.length+"");
for(int i=0;i<pub.length;i++) {
out.writeUTF(pub[i]+ "");
}
Thread.sleep(1000);
int length = Integer.parseInt(in.readUTF());
byte cpub[] = new byte[length];
for(int i=0;i<length;i++) {
String temp = in.readUTF();
cpub[i] = Byte.parseByte(temp);
}
ByteArrayInputStream ckey1 = new ByteArrayInputStream(cpub);
ObjectInputStream ckey = new ObjectInputStream(ckey1);
Key k = (Key) ckey.readObject();
FileOutputStream f2 = new FileOutputStream("W1pub.dat");
ObjectOutputStream b2 = new ObjectOutputStream(f2);
b2.writeObject(k);
KeyAgree.Agree("W1pub.dat","Lpri.dat");
FileInputStream f = new FileInputStream("sb.dat");
byte[] keysb = new byte[24];
f.read(keysb);
System.out.println("公共密钥为:");
for (int i = 0;i<24;i++) {
System.out.print(keysb[i]+" ");
}
System.out.println("\n请输入中缀表达式:");
String infix = inn.nextLine();
String [] str = infix.split(" ");
System.out.println("已传递后缀表达式");
MyBC suffix =new MyBC(str);
String mtoMD5 = DigestPass.MD5(suffix.jieguo);
System.out.println("明文的MD5值为:"+mtoMD5);
out.writeUTF(mtoMD5);
SecretKeySpec k1 = new SecretKeySpec(keysb, "DESede");
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.ENCRYPT_MODE, k1);
byte ptext[] = suffix.jieguo.getBytes("UTF8");
byte ctext[] = cp.doFinal(ptext);
System.out.println("加密后的后缀表达式为:");
for (int i = 0; i < ctext.length; i++) {
System.out.print(ctext[i] + " ");
}
out.writeUTF(ctext.length + "");
for (int i = 0; i < ctext.length; i++) {
out.writeUTF(ctext[i] + "");
}
String result = in.readUTF();
System.out.println("\n已收到计算结果"+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接"+e);
}
}
}
- 服务器端
package 实验五;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.Key;
public class Sever3 {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("双方已断开连接"+e);
}
try{
System.out.println("准备接受对方传来的问题");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
Key_DH.DH("Wpub.dat","Wpri.dat");
int length = Integer.parseInt(in.readUTF());
byte cpub[] = new byte[length];
for(int i=0;i<length;i++) {
String temp = in.readUTF();
cpub[i] = Byte.parseByte(temp);
}
ByteArrayInputStream ckey1 = new ByteArrayInputStream(cpub);
ObjectInputStream ckey = new ObjectInputStream(ckey1);
Key k1 = (Key) ckey.readObject();
FileOutputStream f2 = new FileOutputStream("L1pub.dat");
ObjectOutputStream b2 = new ObjectOutputStream(f2);
b2.writeObject(k1);
FileInputStream my = new FileInputStream("Wpub.dat");
ObjectInputStream mypub = new ObjectInputStream(my);
Key kp = (Key) mypub.readObject();
ByteArrayOutputStream DH = new ByteArrayOutputStream();
ObjectOutputStream myDH = new ObjectOutputStream(DH);
myDH.writeObject(kp);
byte []pub = DH.toByteArray();
out.writeUTF(pub.length+"");
for(int i=0;i<pub.length;i++) {
out.writeUTF(pub[i]+ "");
}
KeyAgree.Agree("L1pub.dat","Wpri.dat");
FileInputStream f = new FileInputStream("sb.dat");
byte[] keysb = new byte[24];
f.read(keysb);
System.out.println("公共密钥为:");
for (int i = 0;i<24;i++) {
System.out.print(keysb[i]+" ");
}
String c = in.readUTF();
SecretKeySpec k = new SecretKeySpec(keysb, "DESede");
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.DECRYPT_MODE, k);
String clength = in.readUTF();
byte ctext[] = new byte[Integer.parseInt(clength)];
for (int i = 0; i < Integer.parseInt(clength); i++) {
String temp = in.readUTF();
ctext[i] = Byte.parseByte(temp);
}
byte[] ptext = cp.doFinal(ctext);
String suffix = new String(ptext, "UTF8");
String [] str = suffix.split(" ");
System.out.println("\n收到问题,解密后缀表达式为:"+suffix);
String mtoMD5 = DigestPass.MD5(suffix);
System.out.println("MD5的值为"+ mtoMD5);
if(mtoMD5.equals(c)) {
System.out.println("传递的MD5值和解密的后缀表达式的MD5值相同,可以解密!");
System.out.println("已传输得出结果:");
MyDC myDC = new MyDC(str);
String answer = String.valueOf(myDC.answer);
out.writeUTF(answer + "");
}
else {
System.out.println("密文有误,不能解密!");
}
Thread.sleep(500);
}catch (Exception e){
System.out.println("双方已断开连接");
}
}
}
实验结果
-
客户端
-
服务器端