Which of the following best describes data at rest versus data in transit and a typical protection for each?

• A. Data at rest is stored on devices; data in transit is moving across networks. Protect at rest with encryption, in transit with TLS/SSL.
• B. Data at rest is copied nightly; data in transit is encrypted with passwords. Protect at rest with TLS, in transit with disk encryption.
• C. Data at rest refers to backups; data in transit refers to live streams. Protect at rest with VPN, in transit with password hashing.
• D. Data at rest is only in the cloud; data in transit is only on local networks. Protect at rest with hashing, in transit with SSL certificates.

Answer: (A)

This tests understanding of where data resides (at rest vs in transit) and how to protect it. Data at rest is information stored on devices such as disks, databases, or backups, while data in transit is information moving across networks between systems. The typical protections are encryption for data at rest and TLS/SSL for data in transit. Encrypting data at rest keeps stored information unreadable if storage media are accessed by an unauthorized party. TLS/SSL, on the other hand, creates a secure, authenticated channel for data as it travels between endpoints, protecting it from eavesdropping and tampering. The other options mix up where data physically resides or misstate the protective measure—for example, encrypting data in transit with passwords isn’t the standard practice, backups aren’t the same as data at rest in this context, VPN is a channel rather than a general protection for rest, and hashing isn’t used to protect data in transit.