Question

Please write in Java in Jgrasp check code before posting Please write in Java in Jgrasp check code before posting

FOP- 2. Write a program that ciphers a plain text message using double transposition scheme and vice versa. [50 Marks) The program should accept five tuples of input: plain text, row, column, permutation of row and columns. An example of encrypted text for the plain text "attack at dawn” is shown below. Plain text: attack at dawn Matrix row size: 5 Matrix column size: 3 Row permutation order: 3, 5, 1, 4,2 Column permutation order: 1, 3,2 Encrypted text: xtawxnattxadako Similarly, your program should decrypt the encrypted text given the encrypted text, matrix row and column sizes, row and column permutation order. An example snapshot of output is shown below: Encrypted text: xtawxnattxadako Matrix row size: 5 Matrix column size: 3 Row permutation order: 3, 5, 1, 4, 2 Column permutation order: 1, 3,2 Plain text: attack at dawn

Please write in Java in Jgrasp check code before posting, will give thumbs up

Answer 1

Hi, here is the solution. Try it and let me know if you need any assistance. This is working in jGRASP as well.

Source & Screens: DoubleTranspositionCipher.java

public class DoubleTranspositionCipher { // private constructor. // prevents creating instances of class private DoubleTranspositionCipher() { } private static char[][] buildMatrix(String message, int rows, int cols) { char[][] matrix = new char[rows][cols]; int pos; char c; for(int i = 0; i < rows; i++) { for(int j = 0; j < cols; j++) { pos = i * cols + j; // if matrix cell is beyond the message length if(pos >= message.length()) { // set as blanks c = ' '; } else { c = message.charAt(pos); } matrix[i][j] = c; } } return matrix; } private static String getColumnTranspositionMessage(char[][] matrix, int rows, int[] colOrder) { StringBuilder codedMessage = new StringBuilder(); for(int i =0; i <rows; i++) { for(int j : colOrder) { codedMessage.append(matrix[i][j-1]); } } return codedMessage.toString(); } private static String getRowTranspositionMessage(char[][] matrix, int cols, int[] rowOrder) { StringBuilder codedMessage = new StringBuilder(); for(int i : rowOrder) { for(int j = 0 ; j < cols; j++) { codedMessage.append(matrix[i-1][j]); } } return codedMessage.toString(); } public static String encrypt(String message, int rows, int cols, int[] rowOrder, int[] colOrder) { // build code matrix char [][] codeMatrix = buildMatrix(message,rows,cols); // perform columnar transposition and get intermediate message String intermediateMessage = getColumnTranspositionMessage(codeMatrix,rows,colOrder); // build code matrix from intermediate message codeMatrix = buildMatrix(intermediateMessage,rows,cols); // perform row transposition String encryptedMessage = getRowTranspositionMessage(codeMatrix,cols,rowOrder); // replace all blanks with x return encryptedMessage.replaceAll(" ","x"); } public static String decrypt(String message, int rows, int cols, int[] rowOrder, int[] colOrder) { // build code matrix char [][] codeMatrix = buildMatrix(message,rows,cols); // perform row transposition String intermediateMessage = getRowTranspositionMessage(codeMatrix,cols,rowOrder); // build code matrix from intermediate message codeMatrix = buildMatrix(intermediateMessage,rows,cols); // perform columnar transposition and get intermediate message String encryptedMessage = getColumnTranspositionMessage(codeMatrix,rows,colOrder); // replace all x with blanks return encryptedMessage.replaceAll("x"," "); } }

public class DoubleTranspositionCipher 4 5 @ // private constructor. // prevents creating instances of class private Double TranspositionCipher() @ private static char[][] buildMatrix(String message, int rows, int cols) char[][] matrix = new char[rows][cols]; int pos; char c; for(int i = 0; i <rows; i++) 14 for(int j = 0; i < cols; j++) pos = i * cols + j; // if matrix cell is beyond the message length if(pos >= message. Length()) // set as blanks c=''; else c = message.charAt(pos); matrix[i][j] = c; 30 } return matrix; 34 private static String getColumn TranspositionMessage(char[][] matrix, int rows, int[] colorder), { StringBuilder codedMessage = new StringBuilder(); for(int i =0; i <rows; i++) 36 for(int j : colorder) 39 codedMessage.append(matrix[i][j-1]); 43 return codedMessage.toString(); 45 @ 46 = private static String getRowTranspositionMessage(char[I] matrix, int cols, int[] rowOrder) { StringBuilder codedMessage = new StringBuilder(); for(int i : rowOrder) 49 50 for(int j = 0; j< cols; j++) 51 codedMessage.append(matrix[i-1][i]); return codedMessage.toString(); 56 57 @ 58 public static String encrypt(String message, int rows, int cols, int[] rowOrder, int[] colorder) { // build code matrix char (JI) codeMatrix = buildMatrix(message, rows, cols); // perform columnar transposition and get intermediate message String intermediateMessage = getColumn TranspositionMessage (codeMatrix, rows, colorder); // build code matrix from intermediate message codeMatrix = buildMatrix(intermediateMessage, rows,cols); // perform row transposition String encryptedMessage = getRowTranspositionMessage(codeMatrix,cols,rowOrder); // replace all blanks with x return encryptedMessage.replaceAll( regex:" ", replacement: "x"); 70 @ public static String decrypt(String message, int rows, int cols, int[] rowOrder, int[] colorder) // build code matrix char (1) codeMatrix = buildMatrix(message, rows,cols); // perform row transposition String intermediateMessage = getRowTranspositionMessage(codeMatrix,cols, rowOrder); // build code matrix from intermediate message codeMatrix = buildMatrix(intermediateMessage, rows, cols); // perform columnar transposition and get intermediate message String encryptedMessage = getColumn TranspositionMessage(codeMatrix,rows, colorder); // replace all x with blanks return encryptedMessage.replaceALL( regex: "X", replacement: ""); 83 }

Source & Screens : CipherDriver.java

import java.util.Scanner; public class CipherDriver { public static void main(String [] args) { String message; int rows,cols; int [] rowOrder, colOrder; Scanner in = new Scanner(System.in); // encrypt System.out.println("ENCRYPTION"); System.out.println("----------"); System.out.print("Plain Text: "); message = in.nextLine(); System.out.print("Matrix row size: "); rows = Integer.parseInt(in.nextLine()); System.out.print("Matrix column size: "); cols = Integer.parseInt(in.nextLine()); rowOrder = new int[rows]; colOrder = new int[cols]; System.out.print("Row permutation order: "); for(int i = 0 ; i < rows; i++) { rowOrder[i] = in.nextInt(); } in.nextLine(); System.out.print("Column permutation order: "); for(int i = 0 ; i < cols; i++) { colOrder[i] = in.nextInt(); } in.nextLine(); System.out.println("Encrypted text: "+ DoubleTranspositionCipher.encrypt(message,rows,cols,rowOrder,colOrder)); // decrypt System.out.println("\n\nDECRYPTION"); System.out.println("----------"); System.out.print("Encrypted text: "); message = in.nextLine(); System.out.print("Matrix row size: "); rows = Integer.parseInt(in.nextLine()); System.out.print("Matrix column size: "); cols = Integer.parseInt(in.nextLine()); rowOrder = new int[rows]; colOrder = new int[cols]; System.out.print("Row permutation order: "); for(int i = 0 ; i < rows; i++) { rowOrder[i] = in.nextInt(); } in.nextLine(); System.out.print("Column permutation order: "); for(int i = 0 ; i < cols; i++) { colOrder[i] = in.nextInt(); } in.nextLine(); System.out.println("Plain text: "+ DoubleTranspositionCipher.decrypt(message,rows,cols,rowOrder,colOrder)); } }

import java.util.Scanner; public class CipherDriver public static void main(String [] args) String message; int rows, cols; int [] rowOrder, colorder; Scanner in = new Scanner(System.in); // encrypt System.out.println("ENCRYPTION"); System.out.println("----------"); System.out.print("Plain Text: "); message = in.nextLine(); System.out.print("Matrix row size: "); rows = Integer.parseInt(in.nextLine()); System.out.print("Matrix column size: "); cols = Integer.parseInt(in.nextLine()); rowOrder = new int[rows]; colOrder = new int[cols]; System.out.print("Row permutation order: "); for(int i = 0; i <rows; i++) rowOrder[i] = in.nextInt(); in.nextLine(); System.out.print("Column permutation order: "); for(int i = 0; i < cols; i++) colorder[i] = in.nextInt(); in.nextLine(); System.out.println("Encrypted text: "+ DoubleTranspositionCipher.encrypt(message, rows, cols, rowOrder, colorder)); // decrypt System.out.println("\n\nDECRYPTION"); System.out.println("----------"); System.out.print("Encrypted text: "); message = in.nextLine(); System.out.print("Matrix row size: "); rows = Integer.parseInt(in.nextLine()); System.out.print("Matrix column size: "); cols = Integer.parseInt(in.nextLine()); rowOrder = new int[rows]; colorder = new int[cols]; System.out.print("Row permutation order: "); for(int i = 0; i <rows; i++) rowOrder[i] = in.nextInt(); in.nextLine(); System.out.print("Column permutation order: "); for(int i = 0; i < cols; i++) colorder[i] = in.nextInt(); in.nextLine(); System.out.println("Plain text: "+ DoubleTranspositionCipher.decrypt(message, rows, cols, rowOrder, colorder));

ENCRYPTION Plain Text: attack at dawn Matrix row size: 5 Matrix column size: 3 Row permutation order: 35 1 4 2 Column permutation order: 1 3 2 Encrypted text: xtawxnattxadako DECRYPTION Encrypted text: xtawxnattxadako Matrix row size: 5 Matrix column size: 3 Row permutation order: 3 5 1 4 2 Column permutation order: 132 Plain text: attack at dawn Process finished with exit code 0

Screenshots from jGRASP

Threads Call Stack 1] CipherDriver.main (CipherDriver.java: 10) pc = 0 Scanner in = new Scanner(System.in); 77 encrypt System.out.println("ENCRYPTION"); System.out.println("---------"); System.out.print("Plain Text: "); message = in.nextLine(); System.out.print("Matrix row size: "); rows = Integer.parseInt(in.nextLine(); System.out.print("Matrix column size: "); cols = Integer.parseInt(in.nextLine(); rowOrder = new int[rows]; colorder = new int[cols]; System.out.print("Row permutation order: "); for(int i = 0; i <rows; i++) rowOrder[i] = in.nextInt(); Variables Eval static : CipherDriver o Arguments L a rgs ->(obj 104 : java.lang. String[0]) java.lang. String Locals in.nextLine(); System.out.print("Column permutation order: "); for(int i = 0; i < cols; i++) colorder[i] = in.nextInt(); in.nextLine(); System.out.println("Encrypted text: "+ DoubleTranspositionCipher.encrypt(message, rows, cols, rowOrder, colorder)); // decrypt System.out.println("\n\nDECRYPTION"); System.out.println("---------"); System.out.print("Encrypted text: "); message = in.nextLine(); System.out.print("Matrix row size: "); rows = Integer.parseInt(in.nextLine(); System.out.print("Matrix column size: "); cols = Integer.parseInt(in.nextLine()); rowOrder = new int[rows]; colorder = new int[cols]; G Grasp 1 9 CipherDriver.java G Double TranspositionCipher.java Compile Messages | GRASP Messages Run 1/0 Interactions End Clear ----GRASP exec: java -Xnoagent -Djava.compiler-NONE -Xdebug -Xrunjdwp:transpor ----GRASP: connected to debugger. ENCRYPTION Help Plain Text: attack at dawn Matrix row size: 5 Matrix column size: 3 Row permutation order: 3 5 1 4 2 Column permutation order: 1 3 2 Encrypted text: xtawxnattxadakc