第五次实验

20144303《Java程序设计》第五次实验

一、实验要求

运行TCP代码，一人服务器，一人客户端
下载加解密代码，先编译运行代码，一人加密一人解密
集成代码，一人加密后通过TCP 发送，加密使用DES或AES，AES或DES加密密钥Key的发送，使用服务器的公钥加密，公钥算法用RSA或者DH

二、实验步骤

这次实验我和张子扬结对编程，我负责设计服务器的部分。

先获取本机的IP地址，输入cmd，然后输入ipconfig。

客户端代码如下：

package net;

import java.math.*;

import java.net.*;

import java.io.*;

 

public class ComputeTCPClient {

 

public static void main(String srgs[]) {

try {

//创建连接特定服务器的指定端口的Socket对象

Socket socket = new Socket("10.0.6.143", 4421);

//获得从服务器端来的网络输入流

BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

//获得从客户端向服务器端输出数据的网络输出W流

PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);

//创建键盘输入流，以便客户端从键盘上输入信息eredWriter(new OutputStreamWriter(socket.getOutputStream())), true);

//创建键盘输入流

BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));

System.out.print("请输入待发送的数据：");

String s = stdin.readLine(); //从键盘读入待发送的数据

String cs = new SEnc().enc(s);

System.out.println("发送到服务器的密文为：" + cs);

//String t=Read.read();

String ck = new Enc_RSA().Enc();

System.out.println("发送到服务器的加密秘钥为：" + ck);

String result = DigestCalc.hash(s);

 

out.println(ck);

out.println(cs);  //通过网络传送到服务器

out.println(result);

 

 

} catch (Exception e) {

System.out.println(e);

} finally {

//stdin.close();

//in.close();

//out.close();

//socket.close();   

}

}

}

服务器代码如下：

package shiyan5;

 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 ComputeTCPServer{
public static void main(String srgs[]) throws Exception 
{
ServerSocket sc = null;
Socket socket=null;
try 
{
sc= new ServerSocket(4421);//创建服务器套接字
System.out.println("端口号:" + sc.getLocalPort());
System.out.println("服务器已经启动...");
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();
BigInteger c=new BigInteger(aline2);
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();
BigInteger m=c.modPow(d,n);
byte[] keykb=m.toByteArray();

//使用DES对密文进行解密
String aline=in.readLine();//读取客户端传送来的数据
byte[] ctext=parseHexStr2Byte(aline);
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");
System.out.println("从客户端接收到信息为："+p); //通过网络输出流返回结果给客户端

//使用Hash函数检测明文完整性
String aline3=in.readLine();
String x=p;
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(result); 

if(aline3.equals(result))
{
System.out.println("匹配成功");
}

out.println("匹配成功");
out.close();
in.close();
sc.close();
} catch (Exception e) {
System.out.println(e);
} 
}
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;  
}  
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();  
}  

}

有关DES加解密部分的代码：

package net;

public class Change {

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(); 

} 

   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; 

}   

}

实验结果截图：