About
Standard CAPTCHA mechanisms don't work well on the mobile web. The goal of the Mobile CAPTCHA project is to embrace the limitations of mobile platforms to create a usable CAPTCHA mechanism that is also secure against bots.
Brainstorming
We followed the IDEO's Brainstorming rules to come up with several potential designs for a mobile-friendly CAPTCHA mechanism, including arranging image fragments, shaking the phone in different patterns, a "Wheel of Fortune" interface, and a social network face recognition.
Contextual Inquiry
We observed users performing tasks where one of the steps was solving a CAPTCHA on a mobile phone, like signing up for a Gmail account or purchasing event tickets on ticketmaster.com. We came up with three design sketches based on these results.
Video Prototype
The design used for our video prototype combines two existing image-recognition CAPTCHA mechanisms into a mobile form factor. First, users need to identify images from a specific category, then they need to trace an outline of the image on their touchscreen.
