What is a primary function of firewalls in computer security?

A primary function of firewalls in computer security is to prevent unauthorized access to networks. Firewalls act as a barrier between trusted internal networks and untrusted external networks, such as the internet. They monitor and control incoming and outgoing network traffic based on predetermined security rules. By doing so, firewalls help to filter out potentially harmful traffic, which could include attempts by intruders to access sensitive data or systems without authorization.

This protective measure is vital for maintaining the integrity and confidentiality of information within an organization. Firewalls can also be configured to allow or block traffic based on specific criteria, which enhances the overall security posture of the network.

The other options do not align with the primary function of firewalls. Encrypting sensitive data is typically accomplished through encryption protocols rather than firewalls. Installing malicious software is the opposite of what firewalls are designed to do, as their purpose is to block such threats. Enhancing system performance, while beneficial, is not the primary role of a firewall; rather, it focuses on maintaining security against unauthorized access.