(a) The Playfair cipher was the first practical digraph substitution cipher.

i. Briefly explain the mechanism of Playfair Cipher Algorithm.

ii. Construct a table for the Playfair Cipher with the keyword EFFECTIVENESS.

iii. Encrypt the phrase: EXAMFORINFORMATIONSECURITY using constructed table for the Playfair Cipher from (a) ii.

iv. Decrypt the sequence: PQFVCKFUFBGMUFYSTIKZKAGWWG using constructed table for the Playfair Cipher from (a) iii.

(b) One of the classical ciphers is the transposition cipher.

i. Given a plaintext meet me at next midnight, illustrate the mechanism of Columnar Transposition Cipher and to find ciphertext for the given plaintext using the transposition cipher.