What security feature requires additional verification for Google Workspace Admins?

The requirement for additional verification for Google Workspace Admins is best exemplified by the use of security keys. Security keys enhance the security of accounts through two-factor authentication (2FA), which involves not only a password but also a physical device that must be used to gain access. This added layer of security helps protect against unauthorized access, particularly important for admins who have elevated privileges and access to sensitive information.

By using security keys, admins must possess the key at the time of login, ensuring that even if their password is compromised, the malicious actor would still need the physical key to gain access to the account. This makes it significantly more difficult for unauthorized users to infiltrate an admin's account. Such measures are critical in organizational environments where data protection and compliance with security standards are paramount.

Other options like biometric authentication and single sign-on could provide additional security measures. However, they do not specifically emphasize the extra verification process that security keys represent for Google Workspace Admins. Firewalls, while important for network security, do not provide the direct account-level authentication that security keys facilitate for access to Google Workspace.