Authentication is primarily concerned with:

Authentication is primarily focused on establishing the identity of users. This process ensures that individuals or entities accessing a system or application are indeed who they claim to be. This verification is often achieved through various means, such as passwords, biometric data, or security tokens.

Focusing on identifying and confirming the legitimacy of users is crucial for maintaining security, as it forms the first line of defense against unauthorized access. Once a user’s identity is authenticated, further permissions or access can be managed based on their verified identity, yet those subsequent actions depend on proper authentication being completed.

In contrast, the other options deal with different aspects of security management. Updating permissions relates more to access control rather than authentication itself, restricting network access involves preventing unauthorized users from connecting but does not itself verify identity, and maintaining system logs pertains to tracking and recording user activity rather than confirming users' identities. Therefore, establishing the identity of users is the core focus of authentication, making it the correct choice in this context.