Completely Automated Public Turing tests to tell Computers and Humans Apart (CAPTCHA) are challengeresponse tests used on the web to distinguish human users from automated bots (von Ahn et al., 2004). In this paper, we present an exploratory analysis of the results obtained from a user study and a heuristic evaluation of captchas on smartphones; we aimed to identify opportunities and guide improvements for captchas on smartphones. Results showed that existing captcha schemes face effectiveness and user satisfaction problems. Among the more severe problems found were the need to often zoom and pan, and too small control buttons. Based on our results, we present deployment and design guidelines for captchas on smartphones. Copyright

Additional Metadata
Keywords CAPTCHAs, Mobile, Security, Smartphones, Usability
Conference 10th International Conference on Security and Cryptography, SECRYPT 2013 - Part of 10th International Joint Conference on E-Business and Telecommunications, ICETE 2013
Citation
Reynaga, G. (Gerardo), & Chiasson, S. (2013). The usability of CAPTCHAs on smartphones. Presented at the 10th International Conference on Security and Cryptography, SECRYPT 2013 - Part of 10th International Joint Conference on E-Business and Telecommunications, ICETE 2013.