Simon R. Lang, Neville I. Williams. Impeding CAPTCHA Breakers with Visual Decryption. In Colin Boyd, Willy Susilo, editors, 8th Australasian Information Security Conference 2010, AISC 2010, Brisbane, Australia, January 2010. Volume 105 of CRPIT, pages 39-46, Australian Computer Society, 2010. [doi]
Abstract is missing.