Please show step-by-step.

3) Answer part I and II: 1) A KDC: IDA || ID|| N1 (Nx is a nonce) 2) KDC A: E( Ka,[ KS || IDB || N1 || E(Kb ,[Ks|| IDA])) 3) A B: E(K., [Ks || IDA]) 4) B A: E(Ks| N2]) 5) A+B: E(Ks|| f(N2)]) 1. For question 3, please explain the process in each line like: line 1 =>......... Line 2=>......... Line 3=>..... line 4 =>......... line 5 =>......... II. Any possible attack and how we can make the approach more secure