In order to ensure the privacy and integrity of the data, connections between firewalls over public
networks should use?

A.
Screened subnets

B.
Digital certificates

C.
Encrypted Virtual Private Networks

D.
Encryption

Explanation:
This is the correct answer, since firewall does not mean “VPN” we have to select “Encrypted Virtual
Private Networks”. With a VPN and encryption we can provide secure communication in a
transparent way for the users between the endpoints achieving “Confidentiality”. This confidentiality
is achieved through encryption, and this encryption relies on encryption algorithms like AES, DES,
CAST and others. Screened Subnet are not related to secure data over public networks, it’s a place to
put our network services accessible from the outside. Digital certificates do not provide
confidentiality, they only provide integrity.