Usability of Passwordless Authentication in Wi-Fi Networks: A Comparative Study of Passkeys and Passwords in Captive Portals

Abstract

Passkeys have recently emerged as a passwordless authentication mechanism, yet their usability in captive portals remains unexplored. This paper presents an empirical, comparative usability study of passkeys and passwords in a Wi-Fi hotspot using a captive portal. We conducted a controlled laboratory experiment with 50 participants following a split-plot design across Android and Windows platforms, using a router implementing the FIDO2CAP protocol. Our results show a tendency for passkeys to be perceived as more usable than passwords during login, although differences are not statistically significant. Independent of the authentication method, captive portal limitations negatively affected user experience and increased error rates. We further found that passkeys are generally easy to configure on both platforms, but platform-specific issues introduce notable usability challenges. Based on quantitative and qualitative findings, we derive design recommendations to improve captive portal authentication, including the introduction of usernameless authentication flows, improved captive portal detection mechanisms, and user interface design changes.

Figures (11)

• Figure 1: Architecture of the captive portal infrastructure used in the laboratory experiment.
• Figure 2: Login user interface in Zitadel, used in the captive portal.
• Figure 3: Histogram of the Affinity for Technology Interaction (ATI) questionnaire among participants.
• Figure 4: Most common authentication methods used by participants in their online accounts.
• Figure 5: Most common authentication methods used by participants to lock their devices.