Java Course Experiment report four Java network programming and security

Beijing Institute of Electronic Technology (BESTI)

Real Inspection report

Course: Java Programming Class: 1352 Name: Lu Songhon No.: 20135229

Score: Instructor: Lou Jia Peng Experimental Date: 2015.6.9

Experiment level: Preview degree: Experiment time: 15:50--20:50

Instrument Group: 29 Compulsory/Elective: Elective experiment number: 04

Experimental Purpose:

1. Mastering the Java Network programming method;

2. Master the method of Java security programming;

3. Comprehensive use of various technologies;

Experiment Content One:

1. Run the textbook on TCP code, pair, one-man server, one-person client.

2. Use the encryption and decryption code package, compile run code, client-side encryption, server decryption.

3. The client encrypts plaintext and sends ciphertext over TCP.

4. Encryption uses Des,des encryption key to send to the server, using the server's public key encryption, public key algorithm using RSA, verify the integrity of sending information using MD5.

Pair network programming

Experiment Code:
Server:

File Name:ComputeTCPServer.java
Import java.net.*;
Import java.io.*;
Import java.security.*;
Import java.security.spec.*;
Import javax.crypto.*;
Import javax.crypto.spec.*;
Import javax.crypto.interfaces.*;
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 (4410);//Create a server socket
SYSTEM.OUT.PRINTLN ("Port number:" + sc.getlocalport ());
SYSTEM.OUT.PRINTLN ("Server has started ...");
Socket = Sc.accept (); Waiting for client connections
SYSTEM.OUT.PRINTLN ("Connection already established");
Get a reference to a network input stream object
BufferedReader in = new BufferedReader (New InputStreamReader (Socket.getinputstream ()));
Get a reference to a network output stream object
PrintWriter out=new PrintWriter (New BufferedWriter (OutputStreamWriter ()), true);

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 ();
System.out.println ("d=" +d);
System.out.println ("n=" +n);
BigInteger M=c.modpow (d,n);
System.out.println ("m=" +m);
Byte[] Keykb=m.tobytearray ();
String Aline3=new string (MT, "UTF8");
String aline3=parsebyte2hexstr (byte buf[]);

String aline=in.readline ();//Read data sent by the client
FileInputStream f2=new FileInputStream ("Keykb1.dat");
int num2=f2.available ();
Byte[] Keykb=new byte[num2];
F2.read (KEYKB);
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 ("received from the client information:" +p); Returns results to the client over a network output stream

/*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 ();
System.out.println ("d=" +d);
System.out.println ("n=" +n);
BigInteger M=c.modpow (d,n);
System.out.println ("m=" +m);
Byte[] Mt=m.tobytearray ();
String Aline3=new string (MT, "UTF8"); */

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 ("match success");
}

Out.println ("match success");
Out.close ();
In.close ();
Sc.close ();
} catch (Exception e) {
System.out.println (e);
}
}
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 * + 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 Computetcpclient {
public static void Main (String srgs[]) throws exception{
try {
Keygenerator kg=keygenerator.getinstance ("Desede");
Kg.init (168);
Secretkey K=kg.generatekey ();
Byte[] ptext2=k.getencoded ();
String Kstr=parsebyte2hexstr (KB);

To create a socket object that connects to a specified port on a specific server
Socket socket = new Socket ("10.1.0.243", 4410);
Get the network input stream from the server side
BufferedReader in = new BufferedReader (New InputStreamReader (Socket.getinputstream ()));
Obtain a network output stream from the client to the server-side output data
PrintWriter out=new PrintWriter (New BufferedWriter (OutputStreamWriter ()), true);
Create a keyboard input stream so that clients can enter information from the keyboard
BufferedReader stdin = new BufferedReader (new InputStreamReader (system.in));

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 ();
System.out.println ("e=" +e);
System.out.println ("n=" +n);
Byte ptext2[]=kstr.getbytes ("UTF8");
BigInteger m=new BigInteger (PTEXT2);
BigInteger C=m.modpow (e,n);
System.out.println ("c=" +c);
String cs=c.tostring ();
OUT.PRINTLN (CS); Transfer over the network to the server

System.out.print ("Please enter data to be sent:");
String S=stdin.readline (); Read the data to be sent from the keyboard
Cipher cp=cipher.getinstance ("Desede");
Cp.init (Cipher.encrypt_mode, k);
Byte ptext[]=s.getbytes ("UTF8");
Byte ctext[]=cp.dofinal (ptext);
String str=parsebyte2hexstr (Ctext);
Out.println (str); Transfer over the network to the server

String x=s;
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);
OUT.PRINTLN (result);

/*s=result;
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 ();
System.out.println ("e=" +e);
System.out.println ("n=" +n);
Byte ptext2[]=s.getbytes ("UTF8");
BigInteger m=new BigInteger (PTEXT2);
BigInteger C=m.modpow (e,n);
System.out.println ("c=" +c);
String cs=c.tostring ();
OUT.PRINTLN (CS); Transfer to server via network */

Str=in.readline ();//Read results from the network input stream
SYSTEM.OUT.PRINTLN ("The result received from the server is:" +STR); Results returned by the output server
}
catch (Exception e) {
System.out.println (e);
}
finally{
Stdin.close ();
In.close ();
Out.close ();
Socket.close ();
}

}
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 * + low);
}
return result;
}
}

Statistics for PSP (Personal software Process) Time:

Step	Time-Consuming ( min )	percent
Requirements analysis	-	12.5%
Design		29.2%
Code implementation	All	29.2%
Test	+	16.7%
Analysis Summary

Summarize:

This experiment, do more than the previous experiments are difficult, no specific detailed experimental steps, the first implementation is very difficult, almost impossible, but later, and the group of students to discuss the study, gradually found the principle of the experiment, so that the experimental process has a look, to the later we all understand how the same thing. Now it seems that it is interesting to understand the experiment. Through these experiments, I learned that the most important thing to learn about the Java language is to master the methods and architecture, and those specific functions and statements are not fully understood or can be applied.

Group members:

Zhu: http://www.cnblogs.com/20135237zero/

Wong Wai Yip: http://www.cnblogs.com/1551127024hwy/

Java Course Experiment report four Java network programming and security