A Review on Various Interactive CAPTCHA Techniques Concerning Web Security

Turing test is a process of determining the involvement of robot in attacking the web security services and segregate them among humans. This test is commonly useful for web based application in the form of CAPTCHA (Completely Automated Public Turing Test to tell Computer and Human Apart) to prevent from unwanted activities,automated access and the harms caused by the robots. CAPTCHA is tentatively very useful in the form of deformed text, mathematical, OTP (One Time Password), Audio, 3D, Graphical and Gaming CAPTCHA. Gaming CAPTCHA is one of the highly secured CAPTCHAs which is trending now. Most of the gaming CAPTCHA are based on simple logics where user can solve it by dragging object to the target position and some are often difficult to solve even by a human due to the difficulty level. A CAPTCHA should be as easier as human can solve within few seconds that would be almost impossible to solve by robot. A system is required which is able to provide better level of accuracy as compare to the existing CAPTCHAs. A system requires an intellectual effort from user to solve the given query. The proposed system will be able to provide such credentials in which some logical moves will be required that can be easily solved by human but it is not possible to score correct moves by robot. Proposed game possess highly graphical interface with attractive interaction which can inspire user to solve CAPTCHA without any annoyance. The motive of this paper is to review the existing CAPTCHA techniques in the field of web security services and provide best level of security that cannot be cracked and able to replace the existing systems.