What type of token can be used for RADIUS authentication?

One-time passwords (OTPs) are widely utilized in RADIUS authentication due to their dynamic nature and added security they provide. RADIUS, which stands for Remote Authentication Dial-In User Service, is a networking protocol that facilitates user authentication, authorization, and accounting for users accessing network services remotely.

OTPs enhance this process by generating a unique password for each authentication attempt, which is valid for a short period. This mitigates the risks associated with password theft, as even if a password were intercepted, it would become invalid quickly. The integration of OTPs with RADIUS allows for two-factor authentication, where the user must provide something they know (like a traditional password) and something they have (the OTP).

In contrast, smart cards, USB keys, and biometric verification can also be utilized for authentication purposes, but they do not align as closely with the traditional use of RADIUS. Smart cards and USB keys typically rely on static or hardware-based authentication methods, and while biometric verification offers strong user identity confirmation, it does not typically integrate with RADIUS protocols in the same manner as OTPs do. Thus, OTPs stand out as the appropriate choice for use in RADIUS authentication contexts.