ABSTRACT
ABSTRACT: CAPTCHA stands for Completely Automatic Public Turing test to tell Computers and Humans Apart. CAPTCHAs are meant to distinguish between humans and software bots and are used to prevent unauthorized access to Internet resources by the bots. A CAPTCHA is a type of challenge-response test, in which a test is generated by the computer program that most humans can pass but computer programs cannot. In this paper, a new CAPTCHA approach is proposed: Human-Intervened CAPTCHA (HI-CAPTCHA). This HI-CAPTCHA strengthens security in Wireless LAN (WLAN)-based mobile applications and systems. For example, in WLAN-based classroom applications, it is used for the identification of the bots as well as for that of genuine users. A genuine user is one who is authorized to use the WLAN system and is responding from inside the classroom.
