postheadericon One Time Pad Encryption Example using Java code

Write a programs to simulate encryption and decryption technique using One Time Pad, algorithm development and Communication between client and server should be done using Java server socket programming.


OneTimePad.java


package bsr;
import java.util.*;
import java.net.*;
import java.io.*;
/*A code from www.bipinrupadiya.com*/
public class OneTimePad
{
public String doEncryption(String s)
{
int i,j;



int randomBitPattern[]=new int[8];
for(i=0;i<7;i++)
{
randomBitPattern[i]=(i%2==0)?1:0;
}

char asc[]=new char[s.length()];
for(i=0;i<s.length();i++)
{
asc[i]=(char)((int)s.charAt(i));
}

//int bin[]=new int[s.length()];
BasicOperation b1=new BasicOperation();
String cipherText=new String("");

for(i=0;i<asc.length;i++)
{
int temp=(int)(asc[i]);
int len=b1.decimalToBinary(temp);
int bintemp[]=new int[7];
int xorlen;
if(len==7)
{
for(j=1;j<=len;j++)
{
bintemp[j-1]=b1.binaryArrayAtPosition(j);
}
//XOR Operation
xorlen=b1.xorop(bintemp,randomBitPattern,len);
}
else
{
//System.out.println("\n less than 7 :"+len);
bintemp[0]=0;
for(j=1;j<=len;j++)
{
bintemp[j]=b1.binaryArrayAtPosition(j);
}
//XOR Operation
xorlen=b1.xorop(bintemp,randomBitPattern,len+1);
}

int xor[]=new int[xorlen];
for(j=0;j<xorlen;j++)
{
xor[j]=b1.xorinArrayAt(j);
cipherText=cipherText+xor[j];
}
cipherText+=" ";
}
return(cipherText);
}
public String doDecryption(String s)
{
int i,j;
//char cipherChar[]=new char[(s.length()/2)];
char cipherChar[]=new char[(s.length())];
int cnt=-1;
for(i=0;i<s.length();i++)
{
//we receive only Ascii of it is allow 0 and 1, do not accept white space
//int ascii=(int)s.charAt(i);
if((int)s.charAt(i)==48 || (int)s.charAt(i)==49 || (int)s.charAt(i)==32)
{
cnt++;
cipherChar[cnt]=s.charAt(i);
}
}
String s1=new String(cipherChar);
System.out.println(" DATA is Received ::"+s1);
String s2[]=s1.split(" ");
int data[]=new int[s2.length];

for(i=0;i<s2.length;i++)
{
data[i]=Integer.parseInt(s2[i]);
}

char randomBitPattern[]=new char[7];
for(i=0;i<7;i++)
{
randomBitPattern[i]=(i%2==0)?'1':'0';
}

BasicOperation b1=new BasicOperation();
String plain=new String("");

//do the XOR Operation
for(i=0;i<s2.length;i++)
{
int xorlen=b1.xorop(s2[i],randomBitPattern);
int xor[]=new int[xorlen];
for(j=0;j<xorlen;j++)
{
xor[j]=b1.xorinArrayAt(j);
plain+=xor[j];
}
plain+=" ";
}

String p[]=plain.split(" ");
BasicOperation ob=new BasicOperation();
int decryptedChar[]=new int[p.length];
char plainTextChar[]=new char[p.length];
for(i=0;i<p.length;i++)
{
decryptedChar[i]=ob.binaryToDecimal(Integer.parseInt(p[i]));
plainTextChar[i]=(char)decryptedChar[i];
}
return(new String(plainTextChar));
}

}

BasicOperation.java


package bsr;
/*A code from www.bipinrupadiya.com*/
public class BasicOperation
{
int bin[] = new int[100];
int xor[] = new int[100];
int temp1[] = new int[100];
int temp2[] = new int[100];

int len;
int xorlen;
//convert binary number to decimal number
public int binaryToDecimal(int myNum)
{
int dec=0,no,i,n=0;
no=myNum;
//Find total digit of no of inupted number
while(no>0)
{
n++;
no=no/10;
}
//Convert inputed number into decimal
no=myNum;
for(i=0;i<n;i++)
{
int temp=no%10;
dec=dec+temp*((int)Math.pow(2,i));
no=no/10;

}
return dec;
}

//convert decimal number to binary number
public int decimalToBinary(int myNum)
{
int j,i=-1,no,n,temp=0;
no=myNum;
int t[]=new int[100];
while(no>0)
{
i++;
temp=no%2;
t[i]=temp;
no=no/2;
}
len=(i+1);
j=-1;
for(i=len;i>=0;i--)
{
j++;
bin[j]=t[i];
}
return len;
}

//find the specific bit value of binary number at given position
public int binaryArrayAtPosition(int pos)
{
return bin[pos];
}

public int xorinArrayAt(int pos)
{
return xor[pos];
}

//perform the binary X-OR operation
public int xorop(int a[],int b[],int arrlen)
{
int i;
for(i=0;i<arrlen;i++)
{
xor[i]=(a[i]==b[i])?0:1;
}
xorlen=i;
return xorlen;
}
//perform the binary X-OR operation
public int xorop(String s,char c[])
{
int temp,i=-1,cnt=-1;
for(i=0;i<s.length();i++)
{
   xor[i]=(s.charAt(i)==c[i])?0:1;
}
xorlen=i;
return xorlen;
}
public int getLen()
{
return len+1;
}

//display binary bit pattern or the array
public void displayBinaryArray()
{
for(int i=0;i<=len;i++)
{
System.out.println("\n Binary Array :"+bin[i]);
}
}
}




MySocket.java


package bsr;
/*A code from www.bipinrupadiya.com*/
import java.util.*;
import java.net.*;
import java.io.*;
public class MySocket
{
String serverName;
int port;
String frame;
public MySocket()
{
this.serverName="localhost";
this.port=6061;
this.frame="BipinRupadiya";
}
public MySocket(int port)
{
this.port=port;
}
public MySocket(String serverName,int port,String frame)
{
this.serverName=serverName;
this.port=port;
this.frame=frame;
}

public void sendFrame(String frame) throws Exception
{
ServerSocket ss=new ServerSocket(port);
Socket s=ss.accept();

byte bFrame[]=frame.getBytes();
OutputStream os=s.getOutputStream();
os.write(bFrame);
ss.close();
s.close();

    }
public String receiveFrame() throws Exception
{
Socket s=new Socket(serverName,port);
InputStream is=s.getInputStream();
BufferedReader br=new BufferedReader(new InputStreamReader(is));
String str=br.readLine();
s.close();
return(str);
    }

}


sender.java

import bsr.*;
/*A code from www.bipinrupadiya.com*/
public class sender
{
public static void main(String args[])throws Exception
{

String myString="BipinRupadiya";
/*
// read data from user
Scanner sc=new Scanner(System.in);
System.out.println("Enter String(only alphabets allowed) :");
myString=sc.next();

*/

OneTimePad obj = new OneTimePad();
String encryptedString=obj.doEncryption(myString);
System.out.println("\nEncryted String : "+encryptedString);
MySocket m = new MySocket();
m.sendFrame(encryptedString);
}

}

receiver.java


 import bsr.*;
public class receiver
{
public static void main(String args[])throws Exception
{

OneTimePad obj = new OneTimePad();
MySocket m = new MySocket();
String encryptedString=m.receiveFrame();
String decryptedString=obj.doDecryption(encryptedString);
System.out.println("\nDecryted String : "+decryptedString);
}
}



To execute this code


  • compile bsr package
  • compile sender.java
  • compile receiver.java
  • open two command prompt
  • in 1st command prompt execute sender.java
  • in 2nd command prompt execute receiver.java


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