Which practice is essential for mobile device security in BYOD?

• A. Device encryption
• B. Cloud-only storage
• C. Public Wi-Fi
• D. Default passwords

Answer: (A)

Protecting data on devices employees bring to work hinges on protecting data at rest. When a BYOD device can be lost, stolen, or accessed by others, encrypting the data stored on that device makes it unreadable without the proper key or passcode. Hardware-backed or full-disk encryption, paired with a strong lock screen, ensures sensitive corporate information stays protected even if the device falls into the wrong hands. This is essential in BYOD because personal devices may contain both personal and company data and cannot rely on the device being kept in a secure corporate environment.

Cloud-only storage does not guard data that remains on the device itself, so encryption is needed to protect local copies. Public Wi-Fi addresses data in transit, not data at rest on the device, so it isn’t the primary protection for BYOD data. Default passwords create another vulnerability but encryption specifically protects the data at rest; it’s most effective when combined with strong authentication to unlock the device.