In this project we undertake the task of semantic labeling of images. An input image is broken into blocks each of which is assigned one of k categories. Inspired by the part-ofspeech tagging techniques used in language processing, we design an discriminative HMM/CRF based tagger to tag the blocks. We learn subcategories for each tag category in an unsupervised manner, and obtain improved perfo...

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...

A Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a widely used security mechanism for constructing a high-confidence proof that the entity interacting with a remote service is actually a human being. Stimulated by the facts that: a) nowadays CAPTCHA challenges are solely based on the Latin alphabet, b) currently Internet population consists in its majori...

We propose a new construct, the Text-Graphics Character (TGC) CAPTCHA, for preventing dictionary attacks against password authentication systems allowing remote access via dumb terminals. Password authentication is commonly used for computer access control. But password authentication systems are prone to dictionary attacks, in which attackers repeatedly attempt to gain access using the entries...

The most common computer authentication method is to use alphanumerical usernames and passwords. This method has been shown to have significant drawbacks. For example, user tends to pick a passwords that can be easily guessed. On the other hand, if a password is hard to guess, then it is often hard to remember. In this paper, we conduct a comprehensive survey of the existing graphical password ...