期刊名称：International Journal of Computer Science and Information Technologies
电子版ISSN：0975-9646
出版年度：2014
卷号：5
期号：6
页码：7501-7503
出版社：TechScience Publications
摘要：CAPTCHAs have become a very popular security mechanism used to prevent automated abuse of online services intended for humans. Different flavors of CAPTCHA can be seen on Internet. However, a wide variety of CAPTCHAs have been successfully attacked by automated programs. This has made CAPTCHA design an interesting area for research. Among various flavors of CAPTCHA text based are most preferable because of its low implementation cost but this category of CAPTCHA can be attacked with very high success rate. To provide stronger and user-friendly text based CAPTCHA, in this paper, we propose three text based CAPTCHA designs- BarCAPTCHA, TransparentCAPTCHA and ThreadCAPTCHA based on the design principle “hard to separate text from background”. The underlying security assumption is that if an automated program cannot locate text in CAPTCHA then it cannot do further processing to identify the characters of it.
关键词：CAPTCHA; security; automated abuse; online;service; text based; design principle
