Which of the following strategies most effectively protects sensitive data at rest in a database?

Comprehensive and Detailed Explanation From Exact Extract:

Tokenization is the most effective method for protecting sensitive data at rest within a database. Tokenization replaces sensitive information—such as credit card numbers, SSNs, or personal identifiers—with meaningless surrogate values (tokens). The actual data is stored securely in a separate token vault, reducing exposure if the primary database is compromised.

Hashing (A) is one-way and protects integrity, not usability, making it inappropriate for data that must later be retrieved. Masking (B) hides data from users but does not secure stored data in the database. Obfuscation (D) makes data harder to understand but is reversible and not intended for strong security.

Security+ SY0-701 identifies tokenization as a key control for data-at-rest protection, especially in regulated industries like finance and healthcare. It prevents attackers from accessing real data even if the database is breached, significantly reducing risk and compliance impact. This aligns with the exam’s emphasis on confidentiality and data protection strategies in stored environments.