please write answers clearly

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 length(s)? 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? 2. Generate the multiplication table for the extension field GF(23) for the case that the irreducible polynomial is P(x) + 1. The multiplication table is in this case a 8 x 8 table 3. Addition and multiplication in G(21): Compute A(x)+B(x) mod P(x) and AC) BCx) mod P(x) in GF(24) using the irreducible polynomial Px)+ I. What is the influence of the choice of the reduction polynomial on the computation? 1) A(x)+1, B(x)x3++1 2)A(x)-x2+1, B(x) x+1 e here to search 4. Compute in AES field GF(2) where the irreducible polynomial is P(x) = x8 + x4 + x3 + x + 1 . Note that Table 42 contains a list of all multiplicative inverses for this field. 5. We consider AES with 128-bit block length and 128-bit key length. What is the output of the first round of AES encryption if the plaintext x consists of sixteen (68)hex (i.e. 01101000 01101000 bit string) and the AES key consists of sixteen (AA)he (i.e., 10101010 10101010 bit string). You can write your final results in a rectangular matrix format. Hints: you'll have to use AES-128 key schedule to get the subkeys kg and k, tirst. Then you can get your A matrix (16 x 16) by x e ko to start your first round encryption steps ByteSub, ShiftRows, MixCol, and AddSubkey (k1). Submission: Put all answers to the five questions in one pdf file and upload it from your handrrittrn) bardcopy to the class on the due day. Your file