Which element is NOT a traditional part of a firewall?

Encryption is not traditionally considered a part of a firewall's core functionality. Firewalls are primarily designed to monitor and control incoming and outgoing network traffic based on predetermined security rules. The main functions they perform include packet filtering, stateful inspection, and application proxying.

Packet filtering involves examining packets sent between devices and allowing or denying them based on established rules. Stateful inspection enhances this by tracking the state of active connections and making decisions based on the context of the traffic, which is a more advanced form of filtering.

An application proxy, on the other hand, acts as an intermediary between users and services, which adds a layer of security and allows for deeper inspection of the application-level traffic.

While encryption can be used in conjunction with firewalls to protect data in transit, it is not a function performed by firewalls themselves. Encryption is primarily a method of securing data, ensuring that it is not readable by unauthorized parties, which is separate from the firewall's primary role of monitoring and controlling traffic.