Affine Cipher Encryption Decryption Source code in Java

Written by Pranshu Bajpai | Join me on Google+ | LinkedIn

Encryption

/*
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package DICAss;
import java.io.*;
/**
 *
 * @author Pranshu
 */
public class DICAss19_AffineCipherEnc {
    public static void main(String[] args) {
        String Msg;
        String CTxt = "";
        
        int a = 5;
        int b = 8;
        int m = 26;
        
        BufferedReader ObjIn = new BufferedReader(
                new InputStreamReader(System.in));
        try{
            System.out.println("Enter your Message(in Caps and without spaces):");
            Msg = ObjIn.readLine();
        
            //ENCRYPTION...
            for (int i = 0 ; i < Msg.length() ; i++){
                CTxt = CTxt + (char)(((a * Msg.charAt(i) + b) % m) + 65);                
            }
            
            System.out.println("Cipher Text :"+ CTxt);
            
            //ENTERING CIPHER TEXT INTO A FILE...
            DICAss0_FileHandling ObjFilHand = new DICAss0_FileHandling();
            ObjFilHand.FileWriteFunc("BealeCipher_CTxt.txt", CTxt);
        }
        catch(Exception err){
            System.err.print("Error: " + err);
        }
    }         
}

Decryption

/*
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package DICAss;

/**
 *
 * @author Pranshu
 */
public class DICAss20_AffineCipherDec {
    public static void main(String[] args) {
        String Msg = "";
        String CTxt;
        
        int a = 5;
        int b = 8;
        int m = 26;
        int a_inv = 0;
        int flag = 0 ;

        //Finding a_inverse...
        for (int i = 0 ; i < 26 ; i++){
            flag = (a * i) % 26;
            if (flag == 1){
                a_inv = i;
            }
        }
        
        try{
            DICAss0_FileHandling ObjFileHand = new DICAss0_FileHandling();
            CTxt = ObjFileHand.FileReadFunc("BealeCipher_CTxt.txt");
            System.out.println("CIPHER TEXT IS :"+ CTxt);
            
        
            //DECRYPTION...
            for (int i = 0 ; i < CTxt.length() ; i++){
                Msg = Msg + (char)(((a_inv * (CTxt.charAt(i) - b)) % 26) + 65);
            }
            
            System.out.println("Original Message :"+ Msg);
        }
        catch(Exception err){
            System.err.print("Error: " + err);
        }
    }         
}

Vignere Cipher Encryption Decryption Source code in Java

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Encryption

/*
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 */
package DICAss;

/**
 *
 * @author Pranshu
 */
public class DICAss14_VignereEnc {
    public static void main(String[] args){
        String Msg = "IAMUNDERATTACK";
        //String Msg = "vaibs";
        String Key = "CRYPTO";
        
        String CTxt = "";
        
        int MsgLen = Msg.length();
        int KeyLen = Key.length();
        
        int i;
        
        //CREATING FINAL KEY TO ENCRYPT THE MESSAGE!!!
        String KeyFinal = "";
        if( MsgLen < KeyLen){
            for( i = 0 ; i < MsgLen ; i++){
                KeyFinal = KeyFinal + Key.charAt(i);
            }
            //System.out.println(KeyFinal);
        }
        else{
            int Div = MsgLen / KeyLen;
            int Rem = MsgLen % KeyLen;
            
            for (i = 0 ; i < Div ; i++){
                KeyFinal = KeyFinal + Key;
            }
            
            for( i = 0 ; i < Rem ; i++){
                KeyFinal = KeyFinal + Key.charAt(i);
            }
            //System.out.println(KeyFinal);
        }
        
        System.out.println("Msg : " + Msg);
        System.out.println("Key : " + KeyFinal);
        
        //ENCRYPTION...
        int temp;
        char c;
        int sum;
        for(i = 0 ; i < MsgLen; i++){
            sum = Msg.charAt(i) + KeyFinal.charAt(i);
            if (sum >= 155 ){
                temp = sum - 90;
            }
            else {
                temp = sum - 64;
            }
                       
            c = (char) temp;
            CTxt = CTxt + c;
        }   
        System.out.println("CiP : " + CTxt);
    }
}

Decryption

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package DICAss;

/**
 *
 * @author Pranshu
 */
public class DICAss15_VignereDec {
    public static void main(String[] args){
        String Msg = "";
        //String Msg = "vaibs";
        String Key = "CRYPTO";
        
        String CTxt = "LSLKHSHJZJNPFC";
        
        int CTxtLen = CTxt.length();
        int KeyLen = Key.length();

        //GENERATING FINAL KEY TO DECRYPT CIPHER TEXT!!!
        int i;
        String KeyFinal = "";
        if( CTxtLen < KeyLen){
            for( i = 0 ; i < CTxtLen ; i++){
                KeyFinal = KeyFinal + Key.charAt(i);
            }
            //System.out.println(KeyFinal);
        }
        else{
            int Div = CTxtLen / KeyLen;
            int Rem = CTxtLen % KeyLen;
            
            for (i = 0 ; i < Div ; i++){
                KeyFinal = KeyFinal + Key;
            }
            
            for( i = 0 ; i < Rem ; i++){
                KeyFinal = KeyFinal + Key.charAt(i);
            }
            //System.out.println(KeyFinal);
        }
        
        System.out.println("CiP : " + CTxt);
        System.out.println("Key : " + KeyFinal);
        
        //DECRYPTION...
        int temp;
        char c;
        int sum;
        
        for(i = 0 ; i < CTxtLen; i++){
            sum = CTxt.charAt(i) - KeyFinal.charAt(i);
            if (sum >= 0 ){
                temp = sum + 64;
            }
            else {
                temp = sum + 90;
            }
                       
            c = (char) temp;
            Msg = Msg + c;
        }   
        System.out.println("Msg : " + Msg);
    }
}

One Time Pad Encryption Decryption Source code in Java

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Encryption

/*
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package DICAss;
import java.util.Random;
import java.io.*;
/**
 *
 * @author Pranshu
 */
public class DICAss17_OneTimePadEnc {
    public static void main(String[] args) {
        try{
            String Msg ;
            String Key = "";
            String CTxt = "";
            
            //taking message from user
            BufferedReader ObjIn  = new BufferedReader(
                    new InputStreamReader(System.in));
            System.out.print("Enter the Message(Without any space and in Block Letters): \n");
            Msg = ObjIn.readLine();
            
            //to Generate random no. between 0-25 and Generating Key
            Random randomGenerator = new Random();
            for (int idx = 1; idx <= Msg.length(); ++idx){
              int randomInt = randomGenerator.nextInt(26);
              Key = Key + (char)(65+randomInt);
            }
            System.out.println("Key: \n" + Key);
            
            //ENCRYPTION...
            int temp;
            char c;
            int sum;
            for(int i = 0 ; i < Msg.length(); i++){
                sum = Msg.charAt(i) + Key.charAt(i);

                if (sum >= 155 ){
                    temp = sum - 90;
                }
                else {
                    temp = sum - 64;
                }

                c = (char) temp;
                CTxt = CTxt + c;
            }   
            System.out.println("CiP : " + CTxt);
            
            //CREATING FILES FOR THE KEY & CIPHER TEXT... FOR TRANSMISSION!!!
            DICAss0_FileHandling ObjFileHand = new DICAss0_FileHandling();            
            ObjFileHand.FileWriteFunc("OTP_Key.txt", Key);
            ObjFileHand.FileWriteFunc("OTP_CipherText.txt", CTxt);
        }
        catch(Exception err){
            System.err.println("Error: " + err);
        }
    }
}

Decryption

/*
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package DICAss;

/**
 *
 * @author Pranshu
 */
public class DICAss18_OneTimePadDec {
    public static void main(String[] args){
        String Msg = "";
        String Key;        
        String CTxt;
        
        DICAss0_FileHandling ObjFileHand = new DICAss0_FileHandling();
        Key = ObjFileHand.FileReadFunc("OTP_Key.txt");
        CTxt = ObjFileHand.FileReadFunc("OTP_CipherText.txt");
                
        //DECRYPTION...
        int temp;
        char c;
        int sum;
        
        for(int i = 0 ; i < CTxt.length(); i++){
            sum = CTxt.charAt(i) - Key.charAt(i);
            if (sum >= 0 ){
                temp = sum + 64;
            }
            else {
                temp = sum + 90;
            }
                       
            c = (char) temp;
            Msg = Msg + c;
        }   
        System.out.println("Msg : " + Msg);
    }
}

Character Frequency Analysis in Java | Source Code | Simple Cryptanalysis

Written by Pranshu Bajpai | Join me on Google+ | LinkedIn

Source Code

/*
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 */
package DICAss;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

/**
 *
 * @author Pranshu
 */

public class DICAss16_CharFrequency {

    
    public static void main(String[] args) throws FileNotFoundException, IOException {
    
        File f = new File("test.txt");
        
        Scanner input = new Scanner(System.in);
        BufferedWriter w = new BufferedWriter(new FileWriter(f));
                    
        System.out.println("Enter text in book");
        
        w.write(input.nextLine());
        
        w.flush();
        w.close();
        
        BufferedReader r = new BufferedReader(new FileReader(f));
        
        String str;
        String alphabets = "abcdefghijklmnopqrstuvwxyz";
        String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String char1 = "";
        String char2 = "";
        String char3 = "";
        String char4 = "";
        
        str = r.readLine();
        System.out.println(str);
        
        char ch;
        char ch1;
        char ch2;
        char ch3 = 0;
        float[] arr = new float[26];
        int k;
        float len;
        
        // for single character frequency...
        for(int i=0; i < alphabets.length(); i++) {
            ch = alphabets.charAt(i);
            ch1 = alpha.charAt(i);
            k = 0;
            for(int j=0; j < str.length(); j++) {
                if((ch == str.charAt(j))||(ch1 == str.charAt(j))) {
                    k++;
                }
            }
        
            System.out.println("frequency of " + alphabets.charAt(i) + "= " + k);
            len = str.length();
            arr[i] = k / len;
           
        }
        
        System.out.println("________________________________________________");
        
        for(int i = 0; i < alphabets.length(); i++) {
            System.out.println("Probability of " + alphabets.charAt(i) + " = " + arr[i]);
        }
        
        // for  character pair frequency...
        System.out.println("________________________________________________");
        
        for(int i = 0; i < 26; i++) {
            ch = (char) alphabets.charAt(i);
            char1 = "";
            char1 = char1 + ch;
            for(int j = 0; j < 26; j++) {
                ch1 = (char) alphabets.charAt(j);
                char2 = "";
                char2 = char2 + ch1;
            
                 k = 0;
                for(int l = 0; l < str.length() - 1; l++) {
                    if((ch == str.charAt(l) && ch1 == str.charAt(l+1))) {
                        k++;
                    }
                        
                }
            
                System.out.println("Frequency for " + char1 + char2 + "= "+k);
            }
        }
        
        System.out.println("________________________________________________");
        
        //for character triplet frequency...
        for(int i = 0; i < 26; i++) {
            ch = (char) alphabets.charAt(i);
            char1 = "";
            char1 = char1 + ch;
            for(int j = 0; j < 26; j++) {
                ch1 = (char) alphabets.charAt(j);
                char2 = "";
                char2 = char2 + ch1;
       
                for(int x = 0; x < 26; x++) {
                    ch2 = (char) alphabets.charAt(x);
                    char3 = "";
                    char3 = char3 + ch2;
                    k = 0;
            
                    for(int l = 0; l < str.length() - 2; l++) {
                        if((ch == str.charAt(l) && ch1 == str.charAt(l+1) 
                                && ch2 == str.charAt(l+2))) {
                            k++;
                        }
                        
                    }
                    
                    System.out.println("for " + char1 + char2 + char3 + "= "+k);                
                }
            }
        }
        
        System.out.println("________________________________________________");
        
        // for character quadruplet frequency...
        for(int i = 0; i < 26; i++) {
            ch = (char) alphabets.charAt(i);
            char1 = "";
            char1 = char1 + ch;
        
            for(int j = 0; j < 26; j++) {
                ch1 = (char) alphabets.charAt(j);
                char2 = "";
                char2 = char2 + ch1;
               
                for(int x = 0; x < 26; x++) {
                    ch2 = (char) alphabets.charAt(x);
                    char3 = "";
                    char3 = char3 + ch2;
               
                    for(int y = 0; y < 26; y++) {
                        ch3 = (char) alphabets.charAt(y);
                        char4 = "";
                        char4 = char4 + ch3;  
                    }
                    
                    k = 0;
                    for(int l = 0; l < str.length() - 3; l++) {
                        if((ch == str.charAt(l) && 
                            ch1 == str.charAt(l+1) && 
                            ch2 == str.charAt(l+2) && 
                            ch3 == str.charAt(l+3))) {
                                k++;
                        }
                    }
                    System.out.println("for " + char1 + char2 + char3 + char4 + "= "+k);                
                }
            }
        }
    }
}

XOR Encryption Decryption Java Source Code

Written by Pranshu Bajpai | Join me on Google+ | LinkedIn

Encryption

package DICAss;

/*
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 */

/**
 *
 * @author Pranshu
 */
public class DICAss10_XOREncryption {
    public static void main(String[] args){
        String Msg = "I AM UNDER ATTACK!";
        char Key = 'k';
        String CTxt = "";
        int xor;
        char temp;
        for(int i = 0 ; i < Msg.length() ; i++){
            xor = Msg.charAt(i) ^ Key;
            temp = (char)xor;
            CTxt = CTxt + temp;
        }        
        
        System.out.println(CTxt);
    }
}

Decryption

package DICAss;

/*
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 */

/**
 *
 * @author Pranshu
 */
public class DICAss11_XORDecryption {
    public static void main(String[] args){
        String CTxt = "\"K*&K>%/.9K*??*( J";
        char Key = 'k';
        String Msg = "";
        int xor;
        char temp;
        for(int i = 0 ; i < CTxt.length() ; i++){
            xor = CTxt.charAt(i) ^ Key;
            temp = (char)xor;
            Msg = Msg + temp;
        }        
        
        System.out.println(Msg);
    }
}