How can user authentication improve network security?

User authentication significantly enhances network security by ensuring that only authorized users are granted access to the network and its resources. When a network employs user authentication, it typically requires individuals to provide credentials—such as a username and password—before they can connect to the network. This process serves as a gatekeeper, helping to verify each user's identity and ensuring that only those with the proper permissions can gain access to sensitive data, applications, and other network resources.

By limiting access to authorized personnel, the risk of unauthorized access, data breaches, and potential malicious activities is reduced. This is critical, as it helps maintain the integrity, confidentiality, and availability of the network. Proper authentication mechanisms can include multifactor authentication, biometrics, and token-based systems, all of which add layers of security beyond simple username and password combinations.

In contrast, the other options describe different security measures or functionalities that do not directly relate to the fundamental purpose of user authentication. For example, encrypting all network traffic focuses on protecting data while it is in transit rather than authenticating users. Monitoring network performance relates to the oversight of network operations rather than user verification. Similarly, creating virtual private networks pertains to establishing secure channels over the internet, not the authentication process itself.