Consider Needham-Schroeder key exchange protocol, which is presented below: Step 1: Alice  Cathy: {Alice || Bob || rand1} kAlice Step 2: Cathy  Alice: {Alice || Bob || rand1 || ksession || {Alice || ksession} kBob} kAlice Step 3: Alice  Bob: {Alice || ksession} kBob Step 4: Bob  Alice: {rand2} ksession Step 5: Alice  Bob: {rand2 – 1} ksession 1. Discuss each of the five steps of Needham-Schroeder protocol in detail. 2. Show how Alice is convinced that she is talking to Bob. 3. Show how Bob is convinced that he is talking to Alice.