What two elements are necessary for the access control system for unattended SCIF entry?

The correct elements necessary for an access control system for unattended Sensitive Compartmented Information Facility (SCIF) entry are an access card and a PIN. This combination ensures a secure method of authentication that requires both something the individual has (the access card) and something the individual knows (the PIN).

Using an access card alone could lead to unauthorized access if someone were to find or steal the card. The addition of the PIN adds an extra layer of security, meaning that even if a card is compromised, access cannot be granted without the correct numerical code. This dual-factor authentication approach aligns with best practices for securing sensitive information by minimizing the risk of unauthorized access.

In contrast, while other options suggest various forms of biometric or digital credentials, they might not necessarily conform to the required standards for unattended SCIF entry or might not be practical for all user scenarios. Each of those alternatives, including fingerprint scanning and password entry, can present vulnerabilities, which is why the use of access cards and PINs is often preferred in high-security environments like SCIFs.