Human Interactive Proofs (HIPs) are automatic reverse Turing tests designed to distinguish between various groups of users. Completely Automatic Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a HIP system that distinguish between humans and malicious computer programs. Many CAPTCHAs have been proposed in the literature that text-graphical based, audio-based, puzzle-based and...

A reading-based CAPTCHA, called ‘ScatterType,’ designed to resist character–segmentation attacks, is described. Its challenges are pseudorandomly synthesized images of text strings rendered in machine-print typefaces: within each image, characters are fragmented using horizontal and vertical cuts, and the fragments are scattered by vertical and horizontal displacements. This scattering is desig...

A novel strategy which works with improved performance in many factors. We have used Open CV, an picture handling tool kit for applying and examining our ideas. We present a new protection basic based on hard AI issues, namely, a novel family of visual protection password techniques built on top of Captcha technology, which we call Captcha as visual security passwords (CaRP). CaRP is both a Cap...

Herein, we propose generating CAPTCHAs through random field simulation and give a novel, effective and efficient algorithm to do so. Indeed, we demonstrate that sufficient information about word tests for easy human recognition is contained in the site marginal probabilities and the site-to-nearby-site covariances and these quantities can be embedded into KNW conditional probabilities, designed...

CAPTCHA is a completely automated program designed to distinguish whether the user is a computer or human. As the problems of Internet security are worsening, it is of great significance to do research on CAPTCHA. This article starts from the recognition of CAPTCHAs, then analyses the weaknesses in its design and gives corresponding recognition proposals according to various weaknesses, finally...

Human Interactive Proofs (HIPs) are automatic reverse Turing tests designed to distinguish between various groups of users. Completely Automatic Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a HIP system that distinguish between humans and malicious computer programs. Many CAPTCHAs have been proposed in the literature that text-graphical based, audio-based, puzzle-based and...

The malware attacks attempt to deplete the cloud services with bogus request which is a major threat in cloud. A mechanism to intensify the login security in cloud is suggested. The concept of CaPGP – CAPTCHA as Puzzle and Graphical Password is introduced because CAPTCHA is one way to discriminate human and malware apart. The computations at the client side are made intensive than on the server...