Consider the SSH protocol in Figure 10.1.
a. Explain precisely how and where Alice is authenticated. What prevents a replay attack?
b. If Trudy is a passive attacker, she cannot determine the key K. Why?
c. Show that if Trudy is an active attacker and she can impersonate Bob, then she can determine the key K that Alice uses in the last message. Explain why this does not break the protocol.
d. What is the purpose of the encrypyting the final message with the key K?