A Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a widely used security defense mechanism that is utilized by service providers to determine whether the entity interacting with their system is a human and not a malicious agent. Motivated by recent research which underpins the necessity for designing more userfriendly CAPTCHA, this paper investigates the ...

The massive and automated access to Web resources through robots has made it essential for Web service providers to make some conclusion about whether the "user" is a human or a robot. A Human Interaction Proof (HIP) like Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) offers a way to make such a distinction. CAPTCHA is a reverse Turing test used by Web serv...

Many security primitives are based on hard mathematical problems. Using hard AI problems for security is emerging as an exciting new paradigm,but has been under explored a novel family of graphical password systems built on top of Captcha technology,which we call Captcha as a graphical passwords (CaRP).. CaRP addresses a such as online guessing attacks, relay attacks, and, if combined withdual-...

Recent document image understanding R&D intended to protect Internet services against abuse by programs is summarized. The accelerating pace of introduction of working CAPTCHAs — completely automatic public Turing tests to tell computers and humans apart — is reported, and the ability of these CAPTCHAs to resist attack is critiqued. Attacks on PARC’s ‘BaffleText’ CAPTCHA by the DIA, CV, and sec...

Completely Automatic Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a HIP (Human interactive Proof) system. CAPTCHAs are used to improve the security of Internet based applications in order to ensure that a web based application which is intended to be used by a human being is not maliciously used by Artificially Intelligent programs called bots. As the current CAPTCHA metho...

Facial/voice-based authentication is becoming increasingly popular (e.g., already adopted by MasterCard and AliPay), because it is easy to use. In particular, users can now authenticate themselves to online services by using their mobile phone to show themselves performing simple tasks like blinking or smiling in front of its built-in camera. Our study shows that many of the publicly available ...

Purpose In this work we argue that it is possible to address discrimination issues that naturally arise in contemporary audio CAPTCHA challenges and potentially enhance the effectiveness of audio CAPTCHA systems by adapting the challenges to the user characteristics. Design/methodology/approach We design a prototype, called PrivCAPTCHA, to offer privacy-preserving, user-centric CAPTCHA challeng...