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...

As protection of web applications are getting more and more important every day, CAPTCHAs are facing booming attention both by users and designers. Nowadays, it is well accepted that using visual concepts enhance security and usability of CAPTCHAs. There exist few major different ideas for designing image CAPTCHAs. Some methods apply a set of modifications such as rotations to the original imag...

Code voting provides an appropriate technology to address the secure platform problem of remote Internet voting, but it is not particularly user-friendly. In this paper, we propose the use of CAPTCHAan acronym standing for Completely Automated Public Turing tests to tell Computers and Humans Apart to improve the user-friendliness of code voting, discuss the security of CAPTCHAbased code voting,...

Efforts to defend against automated attacks on e-commerce services have led to a new security protocol known as a CAPTCHA, a challenge designed to exploit gaps in the perceptual abilities between humans and machines. In this paper, we propose a new paradigm for building CAPTCHA’s which offers simultaneous benefits to both online security and pattern recognition research. We illustrate our discu...

Nowadays, many daily human activities such as education, trade, talks, etc are done by using the Internet. In such things as registration on Internet web sites, hackers write programs to make automatic false registration that waste the resources of the web sites while it may also stop it from functioning. Therefore, human users should be distinguished from computer programs. To this end, this p...