initiate the double transposition

Author: shams-nahid

.idea/workspace.xml

@@ -0,0 +1,107 @@
+let message = 'DEPARTMENTOFCOMPUTERSCIENCEANDENGINEERING';
+let sector = 10;
+
+let transposition = (myString, column, cb) => {
+
+    createMatrix(myString, column, (err, matrix, row) => {
+        let transposedMessage = '';
+        let decryptMessage = '';
+
+        if (err) {
+
+        } else {
+            for (let j=0; j<column; j++) {
+                for (let i=0; i<row; i++) {
+                    if (matrix[i][j] == null) {
+                        decryptMessage += '$';
+                    } else {
+                        transposedMessage += matrix[i][j];
+                        decryptMessage += matrix[i][j];
+                    }
+                }
+            }
+            return cb(null, transposedMessage, decryptMessage, row);
+        }
+    });
+};
+
+let createMatrix = (myString, column, cb) => {
+    myString = myString.split('');
+    let row,
+        length = myString.length,
+        tempRowF = length/column,
+        tempRowR = parseInt(length/column),
+        matrix = new Array();
+
+    if (tempRowR == tempRowF) {
+        row = tempRowR;
+    } else {
+        row = tempRowR + 1;
+    }
+
+    let index = 0;
+
+    for (let i=0; i<row; i++) {
+        matrix[i] = new Array();
+    }
+
+    for (let i=0; i<row; i++) {
+        for (let j=0; j<column; j++) {
+            if (myString[index] == ' ') {
+                matrix[i][j] = '-';
+            } else if (index >= length) {
+                matrix[i][j] = null;
+            } else {
+                matrix[i][j] = myString[index];
+            }
+            index ++;
+        }
+    }
+
+    return cb(null, matrix, row);
+};
+
+let decryptMessage = (encryptedMessage, column, cb) => {
+    encryptedMessage = encryptedMessage.split('');
+    let decryptMessage = '';
+    let reservedMessage = '';
+    let length = encryptedMessage.length - 1;
+    let index = 0;
+    for (let i=0; i<length; i++) {
+        if (encryptedMessage[index] == '$') {
+            reservedMessage += encryptedMessage[index];
+        } else {
+            decryptMessage += encryptedMessage[index];
+            reservedMessage += encryptedMessage[index];
+        }
+
+        index += column;
+
+        if (index >= length) {
+            index = index - length;
+        }
+    }
+    cb(null, decryptMessage, reservedMessage);
+};
+
+transposition(message, sector, (err, encryptMessage, reservedMessage, row) => {
+    console.log('MESSAGE: ' + message + '\n');
+
+    if (err) {
+
+    } else {
+        console.log('AFTER ENCRYPTION');
+        console.log('   Encrypted message: ' + encryptMessage);
+        console.log('   Reserved message:' + reservedMessage);
+        decryptMessage(reservedMessage, row, (err, decryptedMessage, reservedMessage) => {
+            if (err) {
+
+            } else {
+                console.log('AFTER DECRYPTION');
+                console.log('   Decryped message: ' + decryptedMessage);
+                console.log('   Reserved message: ' + reservedMessage);
+            }
+        });
+    }
+});
+

doubleTransposition.js

@@ -1,3 +1,6 @@
+let message = 'DEPARTMENTOFCOMPUTERSCIENCEANDENGINEERING';
+let sector = 10;
+
 let transposition = (myString, column, cb) => {
 
     createMatrix(myString, column, (err, matrix, row) => {
@@ -17,7 +20,7 @@ let transposition = (myString, column, cb) => {
                     }
                 }
             }
-            return cb(null, transposedMessage, decryptMessage);
+            return cb(null, transposedMessage, decryptMessage, row);
         }
     });
 };
@@ -81,14 +84,16 @@ let decryptMessage = (encryptedMessage, column, cb) => {
     cb(null, decryptMessage, reservedMessage);
 };
 
-transposition('DEPARTMENTOFCOMPUTERSCIENCEANDENGINEERING', 10, (err, encryptMessage, reservedMessage) => {
+transposition(message, sector, (err, encryptMessage, reservedMessage, row) => {
+    console.log('MESSAGE: ' + message + '\n');
+
     if (err) {
 
     } else {
         console.log('AFTER ENCRYPTION');
         console.log('   Encrypted message: ' + encryptMessage);
         console.log('   Reserved message:' + reservedMessage);
-        decryptMessage(reservedMessage, 10, (err, decryptedMessage, reservedMessage) => {
+        decryptMessage(reservedMessage, row, (err, decryptedMessage, reservedMessage) => {
             if (err) {
 
             } else {