Making CAPTCHAs clickable

We show how to convert regular keyboard-entry CAPTCHAs into clickable CAPTCHAs. The goal of this conversion is to simplify and speed-up the entry of the CAPTCHA solution, to minimize user frustration and permit the use of CAPTCHAs on devices where they would otherwise be unsuitable. We propose a technique for producing secure clickable CAPTCHAs that are well suited for use on cell phones and other mobile devices. We support the practical viability of our approach by results from a user study, and an analysis of its security guarantees. Categories and Subject Descriptors K.6.5 [Computing Milieux]: Management of Computing and Information Systems—Security and Protection General Terms Security, Human Factors Keywords CAPTCHA, reverse Turing test, usability, mobile devices.

• Type: Conference
• Year: 2008
• Where: WMCSA
• Authors: Richard Chow, Philippe Golle, Markus Jakobsson, Lusha Wang, XiaoFeng Wang
• Keywords: Captchas, Clickable Captchas, Mobile Computing, Regular Keyboard-entry Captchas, WMCSA 2008