Recently, with the spread of online services involving websites, attackers have opportunity to expose these malicious actions. To protect services, A Completely Automated Public Turing Test Tell Computers and Humans Apart (CAPTCHA) is a proposed technique. Since many Arabic countries developed their in Arabic, text-based CAPTCHA has been introduced improve usability for users. Moreover, there e...

To date, CAPTCHAs have served as the first line of defense to prevent unauthorized access by (malicious) bots web-based services, while at same time maintaining a trouble-free experience for human visitors. However, recent work in literature has shown that sophisticated using advancements Machine Learning (ML) can easily bypass existing CAPTCHA-based defenses. This introduces CAPTURE, novel CAP...

This paper proposes a public-key cryptosystem and a short password encryption mode, where traditional hardness assumptions are replaced by specific refinements of the CAPTCHA concept called Decisional and Existential CAPTCHAs. The public-key encryption method, achieving 128-bit security, typically requires from the sender to solve one CAPTCHA. The receiver does not need to resort to any human a...

Prof. von Ahn began his discussion of the possibilities of augmented intelligence with a description of his invention (with colleagues) of the Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) [1], often encountered as a random sequence of distorted letters, which human Web users have to repeat to prove that they are indeed human, rather than a computer progra...