Supporting Learning of an Unfamiliar Authentication Scheme

Difficulties with plaintext passwords are well-documented. Many alternative authentication schemes have been proposed, but a key evaluation metric has typically been ignored: learnability. For wide deployment, some form of tutorial is the most assistance users would be provided. This paper presents the results of two user studies (one local and one on Amazon Mechanical Turk) of 134 total participants. Our studies compared four methods of teaching a new authentication scheme: a single page of instructions, a hypertext tutorial with images, an interactive demo, and a video tutorial. As one may expect, demo and video users invested more time in their tutorials than text and hypertext users. We found few differences in the learnability and security between the conditions, but to our surprise, the hypertext and video tutorials resulted in greater password memorability than the text and demo tutorials.