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

2026-03-26

AI Summary

This study presents the first systematic evaluation of passkey-based authentication usability within Wi-Fi captive portals. Addressing the limitations of traditional password-based methods, the research implements the FIDO2CAP protocol and conducts a controlled user study with 50 participants across Android and Windows platforms, employing a between-subjects crossover design for both quantitative and qualitative analysis. Findings indicate that passkeys are generally perceived as more usable during login—though not statistically significant—while the inherent constraints of captive portals substantially degrade user experience and increase error rates. The work proposes design improvements, including a username-less authentication flow and an enhanced portal detection mechanism, and highlights platform-specific configuration challenges that hinder seamless deployment.

Technology Category

• Humans and AI: User Experience and Usability
• Application Domains: Mobility, Driving & Flight
• Natural Language Processing: Safety and Robustness

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Consent frameworks and practices on the web
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization

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.

Problem

• passwordless authentication
• passkeys
• captive portals
• usability
• Wi-Fi networks

Innovation

• passwordless authentication
• passkeys
• captive portal
• usability study
• FIDO2CAP