Avatar CAPTCHA: Telling computers and humans apart via face classification
Darryl D'Souza, Phani C. Polina, Roman V. Yampolskiy · 2012
This paper introduces Avatar CAPTCHA, an image based approach to distinguish human users from computer programs (bots). The proposed CAPTCHA asks users to identify avatar faces from a set of 12 grayscale images comprised of a mix of human and avatar faces. Experimental results indicate that it can be solved 62% of the time by human users with an average success time of 24 seconds and a positive user rating of 90%. It is designed to be secure against computer programs (bots). Using brute force attack the success rate for a bot to solve it is 1/4096.