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 should click on...

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 ...