See the question below in the description

(answer should be in at least half page or one page).

1-Can you “decrypt” a hash of a massage to get the original message? Explain your answer.
Suppose Alice has a message that she is ready to send to anyone who asks. Thousands of people
want to obtain Alice’s message, but each wants to be sure of the integrity of the message. In this
context, do you think a mac-based or a digital-signature-based integrity scheme is more suitable?
3-Suppose Bob initiates a TCP connection to Trudy who is pretending to be Alice. During the
handshake, Trudy sends Bob Alice’s certificate. In what step of the SSL handshake algorithm will Bob
discover that he is not communicating with Alice?
4- Stateful packet filters maintain two data structures. Name them and briefly describe what they do.