116 Suppose we are using a three message mutual authenticati

(11.6) Suppose we are using a three ­message mutual authentication protocol, and Alice initiates contact with Bob. Let\'s stipulate that Bob sends both a challenge, and a challenge encrypted with a key that only he knows, to Alice. Is the below protocol secure?

Solution

Yes this above mentioned way of communicating is secure as the key shared is available only to Bob and message is encrypted with the key.