To distinguish between human user and computer program to enhance security, a popular test called CAPTCHA is used on Web. CAPTCHA has an important role in preventing Denial Of Service (DOS) attacks in computer networks. There are many different types of CAPTCHA in different languages. Due to the expansion of Persian-language and documents on internet, creating a suitable Persian CAPTCHA seems t...

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 preferabl...

This paper discusses and demonstrates the interplay between system security and user interface convenience in CAPTCHA design, and in particular, mobile device CAPTCHA design. A CAPTCHA is a computer-based security test used to distinguish human users from artificial users, preventing automated abuse of networked resources. As mobile network services improve, we can anticipate that future mobile...

The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) is used to believe that a human is using the web service [1]. For the online services which are been provided in web services is been abused by automated bots over the internet. So CAPTCHA is used as a protection from these malicious programs for web security. But the bots are intelligent enough to break th...

CAPTCHA stands for Completely Automated Public Turing Test to Tell Computer and Human Apart. It is the test that human can pass easily but computer cannot. For example, humans can read distorted text, but current computer programs cannot. For many years, CAPTCHAs have proven very useful for many reputable, Web-based email and application service providers, including social networking sites and ...

“CAPTCHA” stands for Completely Automated Public Turing Test[1] to Tell Computers and Humans Apart[2]. Due to exponential growth of internet, security of web application has become a vital issue and many web applications facing a threat of web bots also known as internet Robot is an automated script which executes over the web forms and occupy web spaces and thus increases network traffic. The ...

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...

The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) has been widely used as a technique that will allow a machine to distinguish between input from a human and that of another machine. The security of current CAPTCHA methods is not sufficient to protect against advanced modern malware. This paper focuses on applying gamification, the use of game elements in ...

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 ...

Information and computer security is supported by passwords. Password is the principal part of authentication process. The traditional authentication method is to use text-based password which is also called alphanumeric password. But it has significant drawbacks. So to overcome vulnerabilities of this traditional password scheme a graphical password scheme is developed. But major drawback of g...