The best control to minimize the risk of unauthorized access to lost company-owned mobile devices is device encryption. Device encryption is a process that transforms data on a device into an unreadable format using a cryptographic key. Device encryption protects the data stored on the device from being accessed by unauthorized parties, even if they bypass the password or PIN protection. Device encryption can also prevent data leakage if the device is disposed of or recycled without proper data sanitization. Password or PIN protection is a basic control that prevents unauthorized access to the device by requiring a secret code or pattern to unlock it. However, password or PIN protection can be easily compromised by brute force attacks, shoulder surfing, or social engineering. Device trackingsoftware is a tool that allows the device owner or administrator to locate, lock, or wipe the device remotely in case of loss or theft. However, device tracking software depends on the device’s network connectivity and GPS functionality, which may not be available or reliable in some situations. Periodic backup is a process that copies the data from the device to another storage location for recovery purposes. Periodic backup can help restore the data in case of loss or damage of the device, but it does not prevent unauthorized access to the data on the device itself. References: CISA ReviewManual (Digital Version), Chapter 5: Protection of Information Assets, Section 5.4: Mobile Devices