A CAPTCHA which humans find to be highly legible and which is designed to resist automatic character–segmentation attacks is described. As first detailed in [BR05], these ‘Sc...
The ScatterType CAPTCHA, designed to resist character– segmentation attacks and shown to be highly legible to human readers, is analyzed for vulnerabilities and is offered for e...
In this paper, a CAPTCHA is presented based on the masking characteristics of the Human Visual System (HVS). Knowing that noise can be masked by high activity regions and showing ...
CAPTCHA is a standard security technology that presents tests to tell computers and humans apart. In this paper, we examine the security of a new CAPTCHA that was deployed until v...
We propose IMAGINATION (IMAge Generation for INternet AuthenticaTION), a system for the generation of attack-resistant, user-friendly, image-based CAPTCHAs. In our system, we prod...