What does the Endpoint sign-in policy utilize when there is missing connectivity to the IDP?

The Endpoint sign-in policy is designed to ensure secure access even in the event of connectivity issues with the Identity Provider (IDP). When connectivity is lost, the system can employ Time-Based One-Time Passwords (TOTP) as a method of authentication. TOTP challenges provide a dynamic and time-sensitive code that users receive through a pre-registered application or device, allowing for secure, two-factor authentication even when the underlying IDP is not reachable. This mechanism enhances security by ensuring that access cannot be granted solely based on static credentials, thus reducing the risk of unauthorized access during periods of connectivity loss.

This ensures that users can still securely sign in while maintaining a high level of protection, which is vital in safeguarding endpoint security. The other methods mentioned do not provide the same level of dynamic authentication necessary for maintaining secure access during connectivity disruptions.