Which security approach restricts access to a system to only approved items?

Which security approach restricts access to a system to only approved items?

• A. Blacklisting
• B. Whitelisting
• C. Cryptography
• D. APT

Answer: (B)

Whitelisting restricts access by allowing only items that are explicitly approved to run or access resources. It creates an allowlist of trusted software, users, or IPs and blocks everything else by default, so only those approved items can operate. This reduces risk from unknown or untrusted software because unlisted items are automatically denied, making it a proactive defense. By contrast, blacklisting blocks known bad items, but new or unknown threats can still slip through. Cryptography protects data through encryption and integrity, not access control of what can run on a system. APT refers to a type of sophisticated attacker, not a protective mechanism. Thus, the approach that ensures access is limited to approved items is whitelisting.

Whitelisting restricts access by allowing only items that are explicitly approved to run or access resources. It creates an allowlist of trusted software, users, or IPs and blocks everything else by default, so only those approved items can operate. This reduces risk from unknown or untrusted software because unlisted items are automatically denied, making it a proactive defense.

By contrast, blacklisting blocks known bad items, but new or unknown threats can still slip through. Cryptography protects data through encryption and integrity, not access control of what can run on a system. APT refers to a type of sophisticated attacker, not a protective mechanism. Thus, the approach that ensures access is limited to approved items is whitelisting.