What is the meaning of “data encryption at rest”?

The phrase "data encryption at rest" specifically refers to the practice of encrypting stored data to safeguard it while it is not actively being accessed or transmitted. This means that data residing on physical storage devices, such as hard drives or cloud storage, is protected by encryption algorithms, ensuring that it remains secure from unauthorized access.

When data is encrypted at rest, it remains unreadable without the proper encryption key, which provides a vital layer of security against potential data breaches and unauthorized access, particularly in scenarios where the storage medium may be compromised.

In contrast, encrypting data during transmission focuses on protecting data as it moves across networks, not when it is stored. Techniques for encrypting backups might be a related concept but do not encompass the full scope of encrypting all stored data. Additionally, decrypting data for access is a separate process that occurs after the data has been encrypted. Thus, the correct choice accurately captures the essence of securing data that is not actively in use.