Part III: Answer the following questions in details (out of 40): [ 5 points each ] 1. Find the totient function o(n) for the following (show all the steps to find the answer): a (51)? b. (43)? 2. Find an integer n so that O(n) = 8. 3. Consider a Feistel cipher (that is shown in the figure below) with 4 rounds. The plaintext is denoted as P = (LPTO, RPT) and the corresponding ciphertext as C = (LPT4, RPT4). What is the ciphertext C, in terms of LPTO, RPT., and the subkeys, for the following round functions (Mangler Functions): F(RPT:-1, K) = RPT-1. From IP output 64 LPT RPT 32 32 KI Mangler Function 32 32 32