Definition
Encryption at Rest protects data stored on media or in information systems by encrypting it while it is not being transmitted or actively processed.
Human Explanation
Data stored on drives, servers or other media remains unreadable to anyone without the appropriate cryptographic keys.
Why it Matters
It protects information from disclosure if a device is stolen, storage media is lost or storage is accessed without authorisation.
Conceptual Boundary
Encryption at Rest protects stored information, but it does not protect data during transmission or active processing.
Practical Perspective
It is most effective when all devices and systems that hold important organisational data are covered.