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

A.
Firewall

B.
NAT

C.
IPSec

D.
MAC address

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 B is incorrect. NAT also works at the network layer, but it does not provide encryption for
data.