) What is preperties or analogies of symm metric eryptography ) The same secret key is used for encryption B) The encryption and C) A safe with one lock D) None of the above decryption function are very similar E) (A). (B), and (C) 6) What mode is illustrated below? A) ECB B) CBF C) OFB D) CBC E) None of the above 7) A function f () is a one-way function if A ) y f(x) is computationally easy and x f-1(y) s computationally easy B) both y = f(x) and x = f-10) is computationally infeasible C) both y f(x) and x f) is computationally easy D) y f(a) is computationally easy and x f 1) is computationally infeasible E) None of the above ) Suppose there are 10 users in a network. How many pairs are required in network if they use symmetric cryptography? A) 21 B) 15 C) 28 D) 30 E) 35