A$.$

IPSec is a suite of protocols for securing networks. Briefly outline how it provides confidentiality, integrity, and authentication.

Given an object O and a subject S$,$ explain what an Access Control List $($ACL$)$ is$.$

Scenario: Consider a computer system with three users$$Alice$,$ Bob, and Cindy. Various files are owned by different users, and their access needs to be managed.

$($a$)$ Create the corresponding access control matrix.

$($b$)$ Cindy gives Alice permission to read cindyrec, and Alice removes Bob$$s ability to read alicerec. Show the new access control matrix.