Captcha

IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY, APRIL 2009 1 Exploiting the Human-Machine Gap in trope Recognition for Designing CAPTCHAs Ritendra Datta, Member, IEEE, Jia Li, of age(p) Member, IEEE, and James Z. Wang, Senior Member, IEEE view Security researchers convey, for long, devised mechanisms to prevent adversaries from conducting automatize network attacks, much(prenominal) as denial-of-service, which lead to signi? brush offt wastage of resources. On the other hand, some(prenominal) attempts have been made to automatically recognize generic reduce tos, make them semantically searchable by heart, annotate them, and associate them with linguistic indexes. In the curriculum of these attempts, the limitations of state-of-the-art algorithms in mimicking benignant day-dream have conk out exposed. In this paper, we explore the victimization of this limitation for potentially preventing automated network attacks. While undistorted natural determin es have been shown to be algorithmically recognizable and searchable by content to moderate levels, controlled distortions of speci?c character and strength can potentially make machine experience harder without affecting human recognition.

This divergency in recognizability makes it a shiny candidate for automated Turing tests called CAPTCHAs which can differentiate humans from machines. We through empirical observation make the application of controlled distortions of varying nature and strength, and their effect on human and machine recognizability. While human recognizability is measured on the footing of a n extensive user study, machine recognizabil! ity is based on memory-based contentbased image retrieval (CBIR) and matching algorithms. We give a circumstantial interpretation of our experimental image CAPTCHA system, IMAGINATION, that uses systematic distortions at its core. A signi? flip research topic within signal analysis, CBIR is really conceived here(predicate) as a tool for an adversary, so as to garter us design more foolproof image CAPTCHAs. might Terms Automated Turing...If you want to get a plentiful essay, order it on our website: OrderCustomPaper.com

If you want to get a full essay, visit our page: write my paper