An Image-Based CAPTCHA Scheme Exploiting Human Appearance Characteristics
Sajida Kalsoom · KSII Transactions on Internet and Information Systems · 2012
CAPTCHAs are automated tests that are there to avoid misuse of computing and information resources by bots.Typical text-based CAPTCHAs are proven to be vulnerable against malicious automated programs.In this paper, we present an image-based CAPTCHA scheme using easily identifiable human appearance characteristics that overcomes the weaknesses of current text-based schemes.We propose and evaluate two applications for our scheme involving 25 participants.Both applications use same characteristics but different classes against those characteristics.Application 1 is optimized for security while application 2 is optimized for usability.Experimental evaluation shows promising results having 83% human success rate with Application 2 as compared to 62% with Application 1.