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User Study on Single Password Authentication

Single password authentication (SPA) schemes are introduced to overcome the challenges of traditional password authentications, which are vulnerable to offline dictionary, phishing, honeypot, and man-in-themiddle attacks. Unlike classical password-based authentication systems, in SPA schemes the user is required to remember only a single password (and a username) for all her accounts, while the password is protected against offline dictionary attacks in a provably secure manner. Several cryptographic SPA solutions were proposed in this decade, some based on cloud storage, and some employing a trusted personal mobile device. However, studies on usability of these novel SPA systems are rare, hardening their deployment and the validation of their practicality. In this paper, we implement two very different SPA systems and assess their usability with the following two comparative experiments: one comparing the state-of-the-art cloud-based browser-extension SPA solution against traditional password-based authentication (where in both cases the user experience is simply entering a username and password), and another comparing the first mobile-application-based SPA solution against two-factor authentication (where, in both cases, in addition to the password, the user needs access to her mobile device). We obtain that the cloud-based SPA system is easier to use than the traditional approach, making it suitable for daily use deployment, and the mobile-based SPA system is as easy as, but less intimidating and more secure than twofactor authentication, making it a better alternative for online banking type deployments. Hence, SPA systems overall constitute a usable alternative to the existing solutions, while providing offline dictionary attack protection.