Problem 1: Suppose we modify the Feistel setup as follows. Divide the plaintext into three equal blocks: Lo, Mo, Ro. Let the key for the ith round be K, and let f be some function that produces the appropriate size output. The ith round encryption is given by This continues for n rounds. Consider the decryption algorithm that starts with the ciphertext An, Bn, Cn and uses the algorithm This continues for n rounds, down to Ao, Bo, Co- Show that A that decryption algorithm returns the plaintext. Li. B, Mi and C Ri for al i, so