Consider a candidate cryptosystem that is used to encrypt a message m with key k where k is an integer chosen randomly between 1 and m/2 and [m] denotes length of the message. If m, is the integer-mapped character i of the message, the ciphertext c; is derived via the following encryption algorithm: Ci = 2m + f (a) How many different unique keys exist for this cryptosystem? (b) Can this scheme be broken using a brute force computational attack? Explain why or why not? (c) Write down the decryption algorithm. That is, show how m, is derived given c, and k.