- 目录
==========
- [实验步骤及截图](#jump2)
- [网络编程与安全-1](#jump2.1)
- [网络编程与安全-2](#jump2.2)
- [网络编程与安全-3](#jump2.3)
- [网络编程与安全-4](#jump2.4)
- [网络编程与安全-5](#jump2.5)
前中后缀表达式
实验步骤及截图
网络编程与安全-1
- 参考
1. 实现中缀表达式转后缀表达式的功能 MyBC.java
2. 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
3. 上传测试代码运行结果截图和码云链接
-
代码
- MyDC（给出某算式的后缀表达式，求值）
- MyDCTester
- MyBC（中缀表达式转后缀表达式）
- MyBCtester
-
截图
网络编程与安全-2
- 注意责任归宿，要会通过测试证明自己没有问题
1. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
2. 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
3. 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
4. 客户端显示服务器发送过来的结果
5. 上传测试结果截图和码云链接
网络编程与安全-3
- 注意责任归宿，要会通过测试证明自己没有问题
1. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
2. 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
3. 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
4. 客户端显示服务器发送过来的结果
5. 上传测试结果截图和码云链接
网络编程与安全-4
网络编程与安全-5
- 代码
- 截图
代码
MyDC
import java.util.StringTokenizer;
import java.util.Stack;
public class MyDC {
String q;
Stack stack;
public MyDC() {
stack = new Stack();
}
void set(String question) { //输入后续排列的字符串
q = question;
}
public Rational get() {
Rational op1 = new Rational();
Rational op2 = new Rational();
Rational result = new Rational();
result.setNumerator(0);
StringTokenizer token = new StringTokenizer(q, " ");
String temp;
while (token.hasMoreTokens()) {
temp = token.nextToken();
if (Isop(temp) == 1) { //遇到操作符，弹出栈顶的两个数进行运算
op2 = (Rational) stack.pop();
op1 = (Rational) stack.pop();//弹出最上面两个操作数
result = cal(temp.charAt(0), op1, op2);//根据运算符进行运算
stack.push(result);//将计算结果压栈
}
else {
Rational num = new Rational();
num.setNumerator(Integer.parseInt(temp));
stack.push(num);//操作数入栈
}
}
return result;
}
Rational cal(char op, Rational a, Rational b) { //对栈顶弹出的两个数进行运算
Rational c = new Rational();
switch (op) {
case '+':
c = a.add(b);
break;
case '-':
c = a.sub(b);
break;
case '*':
c = a.muti(b);
break;
case '÷':
case '/':
if(b.getNumerator()==0) {
System.out.println("生成的算式计算时出现了分母为0的情况！");
System.exit(0);
}
else {
c = a.div(b);
break;
}
default:
System.out.println("Wrong!");
}
return c;
}
int Isop(String op) { //判断是不是运算符
if (op.equals("+") || op.equals("-") || op.equals("*") || op.equals("÷") || op.equals("/")) {
return 1;
}
else {
return 0;
}
}
}
MyDCTester
import java.util.Scanner;
public class MyDCTester {
public static void main (String[] args) {
String expression, again;
int result;
try
{
Scanner in = new Scanner(System.in);
do
{
MyDC evaluator = new MyDC();
System.out.println ("Enter a valid postfix expression: ");
expression = in.nextLine();
result = evaluator.evaluate (expression);
System.out.println();
System.out.println ("That expression equals " + result);
System.out.print ("Evaluate another expression [Y/N]? ");
again = in.nextLine();
System.out.println();
}
while (again.equalsIgnoreCase("y"));
}
catch (Exception IOException)
{
System.out.println("Input exception reported");
}
}
}
MyBC
import java.util.Stack;
public class MyBC {
String C = new String();
String End = ""; //存储数字的字符串
public void ChangeString(String str) {
C = str;
}
public String ChangeOrder() {
Stack store = new Stack(); //创建一个存储字符的栈
for (int i = 0; i < C.length(); i++) {
char op = C.charAt(i); //将索引值为i处的字符的值返回
if (op >= '0' && op <= '9') {
End = End + op;
}
else if (op == '(') {
store.push(op);
}
else if (op == '+' || op == '-' || op == '*' || op == '÷'|| op == '/') {
End = End + " ";
if (store.empty()) {
store.push(op);
}
else if (compareValue(op) > compareValue((char) store.peek())) { //比较运算符优先级
store.push(op);
}
else {
End = End + String.valueOf(store.pop());
i--;
}
}
else if (op == ')') {
while ((char) store.peek() != '(') {
End = End + " " + String.valueOf(store.pop());
}
store.pop();
}
}
while (!store.empty()) {
End = End + " " + String.valueOf(store.pop());
}
return End;
}
public int compareValue(char chi) {
int number = 0;
switch (chi) {
case '(':
number = 1;
break;
case '+':
case '-':
number = 2;
break;
case '*':
case '÷':
number = 3;
break;
case '/':
number = 4;
break;
case ')':
number = 5;
break;
default:
number = 0;
break;
}
return number;
}
}
MyBCTester
import java.util.*;
public class MyBCTester {
public static void main(String[] args) {
String question = "";
String question1 = "";
Scanner scanner = new Scanner(System.in);
System.out.println("请输入题目：");
question = scanner.nextLine();
MyBC change = new MyBC();
change.ChangeString(question);
question1 = change.ChangeOrder();
System.out.println(question1);
MyDC getanswer = new MyDC();
getanswer.set(question1);
Rational answer = getanswer.get();
int a = answer.getNumerator();
int b = answer.getDenominator();
float result = (float)a/b;
System.out.println("结果为（保留两位小数）：");
System.out.println(String.format("%.2f",result));
}
}
Server
import java.io.*;
import java.net.*;
public class Server {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
String question = "";
try {
serverForClient = new ServerSocket(2010);
} catch (IOException e) {
System.out.println(e);
}
System.out.println("等待客户呼叫");
try {
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
while(true) {
question = in.readUTF(); // in读取信息，堵塞状态
System.out.println("服务器收到客户传递的后缀表达式为:" + question);
MyDC getanswer = new MyDC();
getanswer.set(question);
Rational answer = getanswer.get();
int a = answer.getNumerator();
int b = answer.getDenominator();
float result = (float) a / b;
System.out.println("计算出的结果为"+String.format("%.2f",result));
out.writeUTF(String.format("%.2f",result));
Thread.sleep(500);
}
} catch (Exception e) {
System.out.println("客户已断开" + e);
}
}
}
Client
import java.io.*;
import java.net.*;
import java.util.Scanner;
public class Client{
public static void main(String args[]) {
Socket mysocket;
DataInputStream in=null;
DataOutputStream out=null;
Scanner scanner = new Scanner(System.in);
try{
System.out.print("输入服务器的IP:");
String IP = scanner.nextLine();
InetAddress address=InetAddress.getByName(IP);
mysocket = new Socket(address, 2010);
in=new DataInputStream(mysocket.getInputStream());
out=new DataOutputStream(mysocket.getOutputStream());
System.out.println("请输入中缀表达式：");
while (scanner.hasNext()) {
String question = scanner.next();
MyBC change = new MyBC();
change.ChangeString(question);
String question1 = change.ChangeOrder();
System.out.println("后缀表达式为："+question1);
out.writeUTF(question1);
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);
System.out.println("请输入中缀表达式:");
}
}
catch(Exception e) {
System.out.println("服务器已断开"+e);
}
}
}
Serverx
import java.io.*;
import java.net.*;
import javax.crypto.*;
import javax.crypto.spec.*;
public class Serverx {
public static void main(String[] args) throws Exception{
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try {
serverForClient = new ServerSocket(2010);
} catch (IOException e) {
System.out.println(e);
}
System.out.println("等待客户呼叫");
try {
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] + " ");
}
while(true) {
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 question = new String(ptext,"UTF8");
System.out.print("
后缀表达式为："+ question);
MyDC getanswer = new MyDC();
getanswer.set(question);
Rational answer = getanswer.get();
int a = answer.getNumerator();
int b = answer.getDenominator();
float result = (float) a / b;
System.out.println("
计算出的结果为"+String.format("%.2f",result));
out.writeUTF(String.format("%.2f",result));
Thread.sleep(500);
}
} catch (IOException e) {
System.out.println("客户已断开" + e);
}
}
}
Clientx
import java.io.*;
import java.net.*;
import javax.crypto.*;
import java.util.Scanner;
public class Clientx {
public static void main(String args[]) throws Exception{
Socket mysocket;
DataInputStream in=null;
DataOutputStream out=null;
Scanner scanner = new Scanner(System.in);
try {
System.out.print("输入服务器的IP:");
String IP = scanner.nextLine();
InetAddress address=InetAddress.getByName(IP);
mysocket = new Socket(address, 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("
请输入中缀表达式：");
while(scanner.hasNext()) {
String question = scanner.next();
MyBC change = new MyBC();
change.ChangeString(question);
String question1 = change.ChangeOrder();
System.out.println("后缀表达式为："+question1);
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.ENCRYPT_MODE,k);
byte ptext[] = question1.getBytes("UTF8");
byte ctext[] = cp.doFinal(ptext);
out.writeUTF(ctext.length + "");
for(int i=0;i<ctext.length;i++) {
out.writeUTF(ctext[i] +"");
}
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);
System.out.println("请输入中缀表达式:");
}
}
catch (IOException e) {
System.out.println("服务器已断开"+e);
}
}
}
Serverxx
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.*;
public class Serverxx {
public static void main(String[] args) throws Exception {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try {
serverForClient = new ServerSocket(2010);
} catch (IOException e) {
System.out.println(e);
}
System.out.println("等待客户呼叫");
try {
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]+" ");
}
while(true) {
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 question = new String(ptext, "UTF8");
System.out.print("
解密后的后缀表达式为：" + question);
MyDC getanswer = new MyDC();
getanswer.set(question);
Rational answer = getanswer.get();
int a = answer.getNumerator();
int b = answer.getDenominator();
float result = (float) a / b;
System.out.println("
计算出的结果为"+String.format("%.2f",result));
out.writeUTF(String.format("%.2f",result));
Thread.sleep(500);
}
}
catch(Exception e) {
System.out.println("客户已断开" + e);
}
}
}
Clientxx
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.security.*;
import java.util.Scanner;
import java.net.*;
public class Clientxx {
public static void main(String[] args) {
Socket mysocket;
DataInputStream in=null;
DataOutputStream out=null;
Scanner scanner = new Scanner(System.in);
try {
System.out.print("输入服务器的IP:");
String IP = scanner.nextLine();
InetAddress address=InetAddress.getByName(IP);
mysocket = new Socket(address, 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("
请输入中缀表达式：");
while(scanner.hasNext()) {
String question = scanner.next();
MyBC change = new MyBC();
change.ChangeString(question);
String question1 = change.ChangeOrder();
System.out.println("后缀表达式为：" + question1);
SecretKeySpec k1 = new SecretKeySpec(keysb, "DESede");
Cipher cp = Cipher.getInstance("DESede");
cp.init(Cipher.ENCRYPT_MODE, k1);
byte ptext[] = question1.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 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);
System.out.println("请输入中缀表达式:");
}
}
catch (Exception e) {
System.out.println(e);
}
}
}
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 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
import java.io.*;
import java.math.*;
import java.security.*;
import javax.crypto.spec.*;
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);
}
}
Serverxxx
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.*;
public class Serverxxx {
public static void main(String[] args) throws Exception {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
try {
serverForClient = new ServerSocket(2010);
} catch (IOException e) {
System.out.println(e);
}
System.out.println("等待客户呼叫");
try {
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]+" ");
}
while(true) {
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 question = new String(ptext, "UTF8");
System.out.println("
解密后的后缀表达式为：" + question);
String mtoMD5 = DigestPass.MD5(question);
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！");
MyDC getanswer = new MyDC();
getanswer.set(question);
Rational answer = getanswer.get();
int a = answer.getNumerator();
int b = answer.getDenominator();
float result = (float) a / b;
System.out.println("计算出的结果为"+String.format("%.2f",result));
out.writeUTF(String.format("%.2f",result));
}
else {
System.out.println("密文有误，不能解密！");
}
Thread.sleep(500);
}
}
catch(Exception e) {
System.out.println("客户已断开" + e);
}
}
}
Clientxxx
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.Socket;
import java.security.*;
import java.util.Scanner;
import java.net.*;
public class Clientxxx {
public static void main(String[] args) {
Socket mysocket;
DataInputStream in=null;
DataOutputStream out=null;
Scanner scanner = new Scanner(System.in);
try {
System.out.print("输入服务器的IP:");
String IP = scanner.nextLine();
InetAddress address=InetAddress.getByName(IP);
mysocket = new Socket(address, 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("
请输入中缀表达式：");
while(scanner.hasNext()) {
String question = scanner.next();
MyBC change = new MyBC();
change.ChangeString(question);
String question1 = change.ChangeOrder();
System.out.println("后缀表达式为：" + question1);
String mtoMD5 = DigestPass.MD5(question1);
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[] = question1.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 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);
System.out.println("请输入中缀表达式:");
}
}
catch (Exception e) {
System.out.println(e);
}
}
}
DigestPass
import java.security.*;
public class DigestPass{
public static String MD5(String str) throws Exception{
String x=str;
MessageDigest m=MessageDigest.getInstance("MD5");
m.update(x.getBytes("UTF8"));
byte s[ ]=m.digest( );
String result="";
for (int i=0; i<s.length; i++){
result+=Integer.toHexString((0x000000ff & s[i]) |
0xffffff00).substring(6);
}
return result;
}
}