This questions deals with Hill ciphers. The alphabet is considered modulo 26; that is, A=0,...,Z=25.

(a) The ciphertext TIOSID has been encrypted with a Hill cipher with matrix {1 2 }

{4 7} (2 by 2 matrix). Decrypt the ciphertext and justify all the steps

(b) We want to encrypt the plaintext STUDENT FIRST NAME with the Hill cipher of Part (a); for instance, in my case I will need to encrypt the plaintext GUILLERMO. Give a ciphertext and justify all the steps. Note: Consider what you need to do if your first name doesn't have an even number of characters

(c)The ciphertext CIHOLINFO was encrypted by Hill cipher with a 33 matrix. The plaintext is SITCRYPTO. Find the encryption matrix M.