CAPTCHA is standard for providing security for web services. It mainly used to avoid Denial-Of –Service attack. CAPTCHA Completely Automated Public Turing Test to Tell Computers and Humans Apart or it is designed to distinguish automatic bots and human. Many different CAPTCHA were introduced and it is in use. All the CAPTCHA have some disadvantage. Textbased CAPTCHA can be easily identified by ...

Existing CAPTCHA solutions are a major source of user frustration on the Internet today, frequently forcing companies to lose customers and business. Game CAPTCHAs are a promising approach which may make CAPTCHA solving a fun activity for the user. One category of such CAPTCHAs – called Dynamic Cognitive Game (DCG) CAPTCHA – challenges the user to perform a game-like cognitive (or recognition) ...

We present a technique for using a content-based video labeling task as a CAPTCHA. Our video CAPTCHAs are generated from YouTube videos, which contain labels (tags) supplied by the person that uploaded the video. They are graded using a video’s tags, as well as tags from related videos. In a user study involving 184 participants, we were able to increase the average human success rate on our vi...

The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) technique has been an interesting topic for several years. An Arabic CAPTCHA recently proposed serve Arab users. Since there have few scientific studies supporting a systematic design or tuning users, this paper aims analyze the text-based at parameter level by conducting experimental study. Based on result...

Captcha (Completely Automated public Turing test to tell Computers and Humans Apart) system is used to verify whether a user is human or computer program. It’s also known as human Interactive Proof (HIP) and based upon Artificial Intelligence. Captcha is a program that protects websites from web-bots by generating tests that computer cannot pass but human can pass .This paper comprise introduct...

In this paper, we firstly introduce that CAPTCHA technology development and the various type of reading CAPTCHA, sound CAPTCHA, graph CAPTCHA at present. The second, we build one kind of the Chinese CAPTCHA model. The third, a new Chinese CAPTCHA system based on AJAX is proposed, which proceed to generate character characteristic based random problem and answer. On its performance, we show that...

Many security primitives are based on hard mathematical problems. Using hard AI problems for security is emerging as an exciting new paradigm, but has been under-explored. In this paper, we present a new security primitive based on hard AI problems, namely, a novel family of graph-ical password systems built on top of Captcha technology, which we call Captcha as graphical passwords (CaRP). CaRP...

CAPTCHAs are widely used by web applications for the purpose of security and privacy. However, traditional text-based not suitable sighted users much less with visual impairments. To address issue, this paper proposes a new mechanism CAPTCHA called HearAct, which is real-time audio-based that enables easy access The user listens to sound something (the “sound-maker”), he/she must identify what ...

C olor plays a major role in increasing usability in systems ranging from TV remote controls (whose buttons are highlighted in different colors to make them easy to spot) to complicated GUIs (where users’ navigation from one area to another is effectively guided by different colors). When used properly, color can greatly enhance user interface designs.1 Color in interfaces is thus typically a u...

A Captcha is a puzzle that is easy for humans but hard to solve for computers. A formal framework, modelling Captcha puzzles (as hard AI problems), was introduced by Ahn, Blum, Hopper, and Langford ([ABHL03], Eurocrypt 2003). Despite their attractive features and wide adoption in practice, the use of Captcha puzzles for general cryptographic applications has been limited. In this work, we explo...