Q1: Based on Playfair algorithm, if the key is "THE MD FIVE MESSAGE DIGEST ALGORITHM" and the plaintext is "THE MD FIVE MESSAGE DIGEST ALGORITHM WAS DEVELOPED BY RON RIVEST AT MIT" and the ciphertext is "HEMDDMVSMD SRAGSDTGSDIFIBVCLEHEHYGATMSHORNMMCXBRKLSSHIEIMTAEU". Which letter in the key box has been combined with which letter? Note: I not combined with J. (2 points)