Captcha is a popular real user detection or autobot/robot rejection technique used in websites for Desktops. Captcha is also in use in some of the mobile websites. Captcha are difficult to read on the smartphone and portable computer screens. Users stuck in zooming in/zooming out while reading and filling the captcha and other required fields. Old aged users feel it more difficult to view and t...

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...

The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) has been widely used as a technique that will allow a machine to distinguish between input from a human and that of another machine. The security of current CAPTCHA methods is not sufficient to protect against advanced modern malware. This paper focuses on applying gamification, the use of game elements in ...

The effectiveness of CAPTCHA challenges largely depends on being simultaneously easier to solve for humans and harder to solve for bots. In this work we argue that it is possible to enhance the effectiveness of audio CAPTCHA challenges by adapting the challenge to the users’ characteristics. We propose a method for achieving this adaptation while protecting users’ privacy. Moreover, our approac...

CAPTCHA is a technology which has its base in a test called the Turing Test. Alan Turing, proposed this test as a way to examine whether or not machines can think or appear to think like humans. The main purpose of a CAPTCHA is to block form submissions from spam botsthat is automated scripts. Various types of CAPTCHAs are used, which mostly requires users to enter the strings of characters tha...

DESIGNING A FACE DETECTION CAPTCHA Adam C. Day Completely Automated Tests for Telling Computers and Humans Apart (CAPTCHAs) are quickly becoming a standard for security in every online interface that could be the subject to spam or other exploitation. The majority of today's CAPTCHA technologies rely on text-based images, which present the user with a string of distorted characters and asks the...

CAPTCHA stands for Completely Automated Public Turing Test to Tell Computer and Human Apart. It is the test that human can pass easily but computer cannot. For example, humans can read distorted text, but current computer programs cannot. For many years, CAPTCHAs have proven very useful for many reputable, Web-based email and application service providers, including social networking sites and ...

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 ...

CAPTCHAs exploit the gap in the ability between a human and a machine to understand the semantics of specific multimedia content, with vast applications in computer security. In this paper we compare two techniques in automated CAPTCHA solving for text-based CAPTCHA schemes, i.e., classification based on the Vector Space Model (VSM) versus a popular Optical Character Recognition (OCR) engine. F...