Version 2 A n Alice n PRA Bob Now attackers cannot replay (n}PRA Question:What is wrong with this authentication protocol? -No session key is established. -Authentication-mutual identity verification session key establishment -How to fix this problem? 66 Version 2  Now attackers cannot replay {n}PRA.  Question: What is wrong with this authentication protocol? ─ No session key is established. ─ Authentication= mutual identity verification + session key establishment ─ How to fix this problem? Alice Bob A n {n}PRA