Which statement best describes encryption in data security?

Which statement best describes encryption in data security?

• A. Encryption protects data at rest and in transit by converting it into unreadable form without the key
• B. Encryption makes data faster to access
• C. Encryption only applies to physical security
• D. Encryption is a type of firewall

Answer: (A)

Encryption hides information by turning readable data into ciphertext using an algorithm and a key. Only someone with the correct key can decrypt and read it. This protects data both in transit over networks and at rest on storage, because without the key the data remains unreadable even if it’s intercepted or accessed by someone unauthorized. That’s why this statement is the best description—it explicitly covers data in transit and data at rest and explains how protection is achieved.

The other ideas don’t fit as well: encryption doesn’t make data faster to access and can add some processing overhead; it’s a digital protection method, not solely about physical security; and it’s not a firewall, which is a separate control that monitors and blocks network traffic.