Which statement describes data encryption at rest?

Which statement describes data encryption at rest?

• A. Encryption protects data in transit over a network.
• B. Encryption protects data at rest; BitLocker (Windows) and FileVault (macOS) provide device encryption.
• C. Encryption improves CPU speed.
• D. Encryption is only used on mobile devices.

Answer: (B)

Data encryption at rest protects stored data on disk or other non-volatile storage, so the information remains unreadable without the decryption key even if someone gains access to the storage medium. This is exactly what device-level encryption does, with Windows BitLocker and macOS FileVault providing full-disk or device encryption to secure data when the system is off or locked. The other options describe different ideas: encryption in transit protects data as it moves across networks, not while it’s stored; encryption doesn’t speed up performance and can add overhead; and encryption isn’t limited to mobile devices—it’s used on desktops, laptops, servers, and more.

Data encryption at rest protects stored data on disk or other non-volatile storage, so the information remains unreadable without the decryption key even if someone gains access to the storage medium. This is exactly what device-level encryption does, with Windows BitLocker and macOS FileVault providing full-disk or device encryption to secure data when the system is off or locked. The other options describe different ideas: encryption in transit protects data as it moves across networks, not while it’s stored; encryption doesn’t speed up performance and can add overhead; and encryption isn’t limited to mobile devices—it’s used on desktops, laptops, servers, and more.