1. Explain the following concepts briefly but to the point: 1) Symmetric cryptography vs. asymmetric cryptography 2) Kerckhoffs principle 3) Key space vs. key length 4) Confusion vs. diffusion 5) Feistel network vs. Substitution-Permutation Network (SPN) 6) Block cipher vs. stream cipher 7) For AES, what are the block size and key lengths)? How many rounds does AES iterate? 8) What are the four layers in each round of AES? 9) How many subkeys does DES-128 need? What is the length of a subkey? 10) What are the two operations within the AES S-Box