This paper introduces pictorial intelligent system for human identification (PiSHi), an image-based captcha which uses three human cognitive abilities to distinguish humans from machines. The first is the human ability to ...

This paper presents a new semantic image

CAPTCHA, called Multiple SEIMCHA. Multiple SEIMCHA

system warps images by using geometric transformations and a

2d view of warped image is shown to user. Users ...

Recently security problems in the Graphic User Interface (GUI) of applications have become a serious threat for system security. Because much of security experts don\\'t design the GUI from end user\\'s point of view, users ...

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 ...