we show an authentication protocol for the stateless server Bob to authenticate
ID: 3866718 • Letter: W
Question
we show an authentication protocol for the stateless server Bob to authenticate a user Alice, which is not secure. Now let's modify the protocol as follows: Bob is still a stateless server and it sends both a challenge, and the challenge encrypted with a key that only he knows, to Alice. Alice then sends the received encrypted challenge back to Bob, together with the same challenge encrypted with the shared secret key between Alice and Bob
l am Alice C) Is this protocol secure? Explain why or why not.Explanation / Answer
The mentioned protocol is secure.
Bob has to authenticate that it is Alice or not. Alice has replied the challange encrypted witn the shared key between Bob and Alice. If the shared key is correct Bob will be able to decrypt it and can compare the challange after decrypting the other encrypted item which is encrypted by his own key. If they match then it means that Alice has been authenticated.
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