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;
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：
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：
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：
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：
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：
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