What is two-tier verification in SCI access?

• A. Two-tier means two people must log in
• B. It refers to two-factor authentication only
• C. Some compartments require additional authentication or supervisor approval beyond standard clearance
• D. It's optional for high-clearance staff

Answer: (C)

Two-tier verification means there are two gates to access a given SCI compartment: you must have the overall SCI clearance, and you must also be explicitly authorized for that specific compartment, often requiring extra authentication steps or supervisor approval. This adds a compartment-level check beyond just holding clearance, ensuring you only access information you need to know. It isn’t simply two people logging in, nor is it limited to two-factor authentication, and it isn’t optional for those with high clearance—additional authorization is still required for certain compartments.