Which security measure facilitates user accountability and tracking through verified access?

User accountability and tracking primarily rely on controlled access to systems and data. Physical access controls are security measures that define who can enter specific areas, whether physical locations or the logical environment of an IT system. These measures often include security badges, biometric scanners, or access logs that track when and who accessed particular resources.

By implementing physical access controls, organizations can ensure that only authorized personnel have access to sensitive equipment, data centers, or critical systems. This not only protects the assets from unauthorized use but also facilitates accountability since each access event can be logged and monitored. If a security breach occurs, having detailed records of who accessed certain areas can help investigators identify responsible individuals.

While the other options contribute to security in different ways, they do not primarily focus on user accountability in the same manner as physical access controls do. Firewalls protect networks from unauthorized access but do not track individual user activities, encrypted data transfer ensures the confidentiality and integrity of data but does not provide tracking features, and intrusion detection systems monitor for abnormal activity but are not specifically designed for verifying access by individual users.