Cryptographic protocols

Question 1

Mention 2 attack against cryptographic protocols and how to mitigate them

Answer 1

1. Replay attacks.
   Eve in the middle can intercept the messages of alice and send the exact same message to bob, bob cant know that it is coming from him. Solution: Nonces.
2. Oracle attacks.
   Some entities like AS can help us get information to make Bob think we are alice.