Many CAPTCHA proposals have shortcomings in their design or implementation that make themmuch weaker than intended. In this paper we study Captcha2, a commercial algorithm, as a means of showing typical flaws that make many CAPTCHAs prone to successful low-cost attacks. The attack we present makes no use of any AI techniques, not affecting the resilience of the original AI problem this CAPTCHA ...

Many web-based services such as email, search engines, and polling sites are being abused by spammers via computer programs known as bots. This problem has bred a new research area called Human Interactive Proofs (HIP) and a testing device called CAPTCHA, which aims to protect services from malevolent attacks by distinguishing bots from human users. In the past decade, researchers have focused ...

CAPTCHAs are a widely deployed mechanism to distinguish a legitimate human user from a computerized program trying to abuse online services. Attackers, however, have devised a clever and an economical way to bypass the security provided by CAPTCHAs by simply relaying CAPTCHA challenges to remote human-solvers. Most existing varieties of CAPTCHAs are completely vulnerable to such relay attacks, ...

The massive and automated access to Web resources through robots has made it essential for Web service providers to make some conclusion about whether the "user" is a human or a robot. A Human Interaction Proof (HIP) like Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) offers a way to make such a distinction. CAPTCHA is a reverse Turing test used by Web serv...

This work focuses on development of an alternative aural CAPTCHA technology based on a speech transcription task. The principal goals are (1) to provide a better quality of service for visually impaired web users who currently have few alternatives for accessing web services protected by CAPTCHAs based on visual perception tasks, (2) as a side effect of CAPTCHA use, collect meaning data, such a...

Completely Automatic Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a HIP (Human interactive Proof) system. CAPTCHAs are used to improve the security of Internet based applications in order to ensure that a web based application which is intended to be used by a human being is not maliciously used by Artificially Intelligent programs called bots. As the current CAPTCHA metho...

Video CAPTCHA improves the usability while reducing the attack success rate compared to a conventional text-based CAPTCHA. However, it remains vulnerable to OCR attacks. Thus, we proposed to use inpainting algorithms to remove the contained text in the video frames, so that the OCR success rate can be reduced without introducing unwanted artifacts that displease the endusers. We implemented Ber...

CAPTCHAs is Turing test are used to distinguish whether a user is a human or a computer. Till today huge number of CAPTCHA schema have been suggest or put forth and applied on miscellaneous websites to secure online services (SOS) from automated decaptcha programs. So development of a good CAPTCHA scheme that is both secure by automated recognition and human usable is an important research prob...

388 ISSN: 2278 – 1323 All Rights Reserved © 2015 IJARCET  Abstract: A new security primitive for new graphical authentication scheme based on hard artificial intelligence problems. Number of graphical password scheme has been proposed as options to traditional to text password authentication, namely a new family of graphical password system for Captcha technology with the level of security. We...

In this article, we’ve tried to examine the hypothesis of the robustness of a form by using CAPTCHA against CSRF and login CSRF attacks. Our investigations showed that unlike public opinion, common attacks to bypass CAPTCHAs such as Optical Character Recognition (OCR) and 3rd party human attacks are not applicable in the CSRF case and instead, Clickjacking is the most important scenario of CSRF...