Encrypt the Message "HELLO MY DEARZ" using Transposition Cipher with \(Key…

Key idea: cipher column 1 = plaintext column 2; cipher column 2 = plaintext column 4; cipher column 3 = plaintext column 1; cipher column 4 = plaintext column 3.

1. Step 1: Remove spaces from the message: HELLO MY DEARZ → HELLOMYDEARZ (12 characters).

2. Step 2: Write the plaintext in rows of 4 (since the key length is 4):

   Row 1: H E L L

   Row 2: O M Y D

   Row 3: E A R Z

3. Step 3: Apply the column mapping to each row: new columns = [old column2, old column4, old column1, old column3].

   Row 1 → E L H L (from old columns 2,4,1,3)

   Row 2 → M D O Y

   Row 3 → A Z E R

4. Step 4: Read the ciphertext row-wise (grouped by rows of 4 for readability): ELHL MDOY AZER. This is the encrypted message.