Which of the following most securely protects data at rest?

AES-256 is a symmetric encryption algorithm widely used to protect data at rest by converting plaintext into ciphertext that is unreadable without the proper key. It provides strong confidentiality and is a standard for encrypting stored data.

TLS 1.2 (A) secures data in transit, not at rest. Masking (C) obscures data but typically for display or limited use and is reversible. Salting (D) is used alongside hashing to protect passwords and data integrity but does not encrypt data.

Encryption with AES-256 is recognized as a best practice for securing stored data in the Security+ Cryptography and General Security Concepts domains【6:Chapter 7†CompTIA Security+ Study Guide】.