Version 3 A n Alice (n,Kab PRA Bob Kab denotes a session key Question:What is wrong with this authentication protocol? -Answer:Attackers can see Kab because they know Alice's public key. -How to fix this problem? 77 Version 3  Question: What is wrong with this authentication protocol? ─ Answer: Attackers can see Kab because they know Alice’s public key. ─ How to fix this problem? Alice Bob A n {n, Kab}PRA Kab denotes a session key