Which of the following is a method used in physical security controls to prevent unauthorized access?

A method used in physical security controls to prevent unauthorized access is the access control vestibule, often referred to as a mantrap. This system consists of a small space with two sets of interlocking doors. It requires a person to enter an initial door, which then closes before the second door can be opened. This mechanism acts as a barrier that prevents unauthorized individuals from accessing secure areas, ensuring that only authorized personnel are allowed entry.

The effectiveness of a mantrap lies in its ability to limit access at a controlled checkpoint, making it difficult for potential intruders to bypass security measures. Additionally, it allows security personnel to monitor who enters and exits a secure area, which further enhances physical security.

In contrast, the other options focus primarily on data or digital security and are not designed to physically control access to secure locations. Data Loss Prevention (DLP) pertains to safeguarding sensitive information from being lost or accessed without authorization, while file integrity checks deal with ensuring that data has not been altered or corrupted over time. Cloud storage solutions, on the other hand, provide a means of storing data remotely and do not inherently provide physical access controls.