Which protocol provides secure network-layer communications by encrypting IP packets?

• A. IP Security
• B. Transport Layer Security
• C. Secure Shell
• D. Hypertext Transfer Protocol Secure

Answer: (A)

Securing communications at the network layer by encrypting IP packets is achieved by IPsec. IPsec operates below the transport and application layers, protecting the actual IP packets as they travel between hosts or networks. It provides confidentiality, integrity, and authentication, and can run in tunnel or transport mode to safeguard traffic across networks.

The other protocols secure data at higher layers. Transport Layer Security, SSH, and HTTPS protect the payload of specific connections between endpoints (such as a web page or a remote login session) but do not encrypt the IP packets themselves at the network layer.