International Journal of Computer Applications |
Foundation of Computer Science (FCS), NY, USA |
Volume 75 - Number 10 |
Year of Publication: 2013 |
Authors: Maddela Shireesha, V. B. Gaikwad |
10.5120/13149-0573 |
Maddela Shireesha, V. B. Gaikwad . Performance Evaluation of CAPTCHA WORD RANKING Algorithm to Break Video CAPTCHA. International Journal of Computer Applications. 75, 10 ( August 2013), 30-35. DOI=10.5120/13149-0573
CAPTCHA – Completely Automated Public Turing test to tell Computer and Humans Apart, CAPTCHAs, on web employed as automated filters to distinguish humans and automated bots to prevent fraud and vandalistic activities such as spamming, automated bot-based account creation and corrupting websites by reducing the availability of site resources to legitimate users. At the moment, Captcha such as Text or image based, Math, and Audio have been broken accurately by bots and proven as less robust. Up recent, to address automated bot fraud activities and attacks a more robust CAPTCHA introduced called Video CAPTCHA. The Video Captcha is a captcha with moving letters and challenge will be given as to enter only few letters with specified color (for example enter only red color letters from moving letters) from moving letters. That means, breaking a captcha with motion along with specified color (red color) becomes difficult and tough job for bots. Moreover, this paper addresses a fact that like other traditional Captchas abovementioned, intelligent bot programs can able to break Video CAPTCHA too. Here, the paper described a novel schema to break Video CAPTCHA and procedure to sequentially break Video CAPTCHA. Yet, this research paper also covers how the implemented captcha breaking algorithm named CAPTCHA WORD RANKING algorithm breaks the Video CAPTCHA easily and effectively. Consequently, this experiment is conducted in an ethical manner and the implemented CAPTCHA WORD RANKING Algorithm only works with own created Video CAPTCHA samples where each sample ends with red color moving letters and captcha is moving from right to left in horizontal direction. Further, discussed the results of Static and Video Captcha samples with their breaking time, followed by performance evaluation of CAPTCHA WORD RANKING algorithm in terms of coverage, precision and accuracy. Subsequently, described the status (success/failure) of captcha samples in graphical representation. Finally, specified the experimental results, role of captcha application and backend database followed by implementation screen shots of some broken Video CAPTCHAs.