Which
of the following protects against unauthorized access to confidential information via encryption and
works at the network layer?

A.
Firewall

B.
NAT

C.
MAC address

D.
IPSec

Explanation:
Internet Protocol security (IPSec) protects against data manipulation and unauthorized
access to confidential information via encryption and
works at the network layer.
IPSec provides machine-level authentication as well as data encryption. It is used for VPN
connections that use the L2TP protocol. It secures
both data and password.
Answer option B is incorrect. NAT also works at the network layer, but it does not provide
encryption for data.