05064264

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05064264 Chew, Monica Tygar, J.D. Image recognition CAPTCHAs. Zhang, Kan (ed.) et al., Information security. 7th international conference, ISC 2004, Palo Alto, CA, USA, September 27--29, 2004. Proceedings. Berlin: Springer (ISBN 3-540-23208-7/pbk). Lecture Notes in Computer Science 3225, 268-279 (2004). 2004 Berlin: Springer EN

doi:10.1007/b100936

Summary: CAPTCHAs are tests that distinguish humans from software robots in an online environment. We propose and implement three CAPTCHAs based on naming images, distinguishing images, and identifying an anomalous image out of a set. Novel contributions include proposals for two new CAPTCHAs, the first user study on image recognition CAPTCHAs, and a new metric for evaluating CAPTCHAs.