For each of the following cases, design a mutual authentication and key establishment protocol that uses public key cryptography and minimizes the number of messages. a. Use a timestamp to...

For each of the following cases, design a mutual authentication and key establishment protocol that uses public key cryptography and minimizes the number of messages.

a. Use a timestamp to authenticate Alice and a nonce to authenticate Bob.

b. Use a nonce to authenticate Alice and a timestamp to authenticate Bob.