Text CAPTCHA has been an effective means to protect online systems from spams and abuses caused by automatic scripts which pretend to be human beings. However, nearly all the Text CAPTCHA designs in nowadays are based on English characters, which may not be the most userfriendly option for non-English speakers. Therefore, under the background of globalization, there is an increasing interest in...

Many security primitives are based on hard mathematical problems. Using hard AI problems for security is emerging as an exciting new paradigm, but has been under-explored. In this paper, we present a new security primitive based on hard AI problems, namely, a novel family of graph-ical password systems built on top of Captcha technology, which we call Captcha as graphical passwords (CaRP). CaRP...

As protection of web applications are getting more and more important every day, CAPTCHAs are facing booming attention both by users and designers. Nowadays, it is well accepted that using visual concepts enhance security and usability of CAPTCHAs. There exist few major different ideas for designing image CAPTCHAs. Some methods apply a set of modifications such as rotations to the original imag...

problems, namely,a novel family of graphical password systems built on top of Captcha Zoo is a Captcha scheme which uses 3D models of horse and dog. mathematical concept related to 3D password, applications of scheme etc. Moreover, Pass. Point – is a recall-based graphical password schema, where a (2) Fawaz A. Alsulaiman and Abdulmotaleb El Saddik, “A Novel 3D. Graphical. also offers a novel ap...

Improvements in image understanding technologies are making it possible for computers to pass traditional CAPTCHA tests with high probability. This suggests the need for new kinds of tasks that are easy to accomplish for humans but remain difficult for computers. In this paper, we introduce Fluency CAPTCHA (FluTCHA), a novel method to distinguish humans from computers using the fact that humans...

Any Web user is a potential knowledge contributor, but it remains a challenge to make them devote their time contributing to some purpose. In order to align individual with social interests, we selected the CAPTCHA Web resource protection application to embed knowledge elicitation within the users' main task of accessing a Web resource. Consequently, unlike previous knowledge acquisition approa...