From 254cc94b85d6732e3c119d8a832179f08a79a4c9 Mon Sep 17 00:00:00 2001
From: Dilrose Reji <70878223+dilroseR@users.noreply.github.com>
Date: Tue, 12 Oct 2021 11:45:35 +0530
Subject: [PATCH] Add product cipher (#2529)

---
 Ciphers/ProductCipher.java | 72 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 Ciphers/ProductCipher.java

diff --git a/Ciphers/ProductCipher.java b/Ciphers/ProductCipher.java
new file mode 100644
index 000000000..ce6b088d7
--- /dev/null
+++ b/Ciphers/ProductCipher.java
@@ -0,0 +1,72 @@
+package Ciphers;
+
+import java.util.Scanner;
+
+class ProductCipher {
+
+    public static void main(String args[]) {
+        Scanner sc = new Scanner(System.in);
+        System.out.println("Enter the input to be encrypted: ");
+        String substitutionInput = sc.nextLine();
+        System.out.println(" ");
+        System.out.println("Enter a number: ");
+        int n = sc.nextInt();
+
+        // Substitution encryption
+        StringBuffer substitutionOutput = new StringBuffer();
+        for (int i = 0; i < substitutionInput.length(); i++) {
+            char c = substitutionInput.charAt(i);
+            substitutionOutput.append((char) (c + 5));
+        }
+        System.out.println(" ");
+        System.out.println("Substituted text: ");
+        System.out.println(substitutionOutput);
+
+        // Transposition encryption
+        String transpositionInput = substitutionOutput.toString();
+        int modulus;
+        if ((modulus = transpositionInput.length() % n) != 0) {
+            modulus = n - modulus;
+
+            for (; modulus != 0; modulus--) {
+                transpositionInput += "/";
+            }
+        }
+        StringBuffer transpositionOutput = new StringBuffer();
+        System.out.println(" ");
+        System.out.println("Transposition Matrix: ");
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < transpositionInput.length() / n; j++) {
+                char c = transpositionInput.charAt(i + (j * n));
+                System.out.print(c);
+                transpositionOutput.append(c);
+            }
+            System.out.println();
+        }
+        System.out.println(" ");
+        System.out.println("Final encrypted text: ");
+        System.out.println(transpositionOutput);
+
+        // Transposition decryption
+        n = transpositionOutput.length() / n;
+        StringBuffer transpositionPlaintext = new StringBuffer();
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < transpositionOutput.length() / n; j++) {
+                char c = transpositionOutput.charAt(i + (j * n));
+                transpositionPlaintext.append(c);
+            }
+        }
+
+        // Substitution decryption
+        StringBuffer plaintext = new StringBuffer();
+        for (int i = 0; i < transpositionPlaintext.length(); i++) {
+            char c = transpositionPlaintext.charAt(i);
+            plaintext.append((char) (c - 5));
+        }
+
+        System.out.println("Plaintext: ");
+        System.out.println(plaintext);
+        sc.close();
+    }
+
+}