1. Answer the following with regards to symmetric encryption algorithms and Feistel Cipher (shown in Figure 1): (a) Explain the terms diffusion and confusion. (b) Explain why diffusion and confusion are desirable properties of symmetric encryption algorithms. (c) For each of the following Feistel Cipher design considerations explain whether it contributes to diffusion, confusion, or both and why? . The F function; . The XOR of the first half of the input to the round with the output of the F function; . The plaintext/ciphertext block size; . The Key expansion (round key algorithm) Round Input LE RE Kn Round Key LE RE n+1 n+1 Round Output Figure 1: A single round of classic Feistel Cipher encryption 15 Marks ]