Bob wants to send Alice a large message m. 1) Design a protocol that only uses secret key cryptography to protect the confidentiality and integrity of the message, assuming that Alice and Bob already share a secret key k beforehand. Give the format of the message (i.e., message components) sent from Bob to Alice. 2) Design a protocol that could use both public key cryptography and secret key cryptography to protect the confidentiality and the integrity of the message, assuming that Alice and Bob already know each other's public key beforehand. Suppose Alice's pair is ; Bob's pair is . Give the format of the message (i.e., message components) sent from Bob to Alice.