Evolution in the world of internet has given rise to several online attacks and the most common attack is phishing. Victims are tricked into providing such information by a combination of spoofing techniques and social engineering. Phishing is an attempt by an individual or a group to acquire sensitive information such as usernames, passwords, and credit card details from unsuspecting victims. ...

As one of the advanced Completely Automated Public Turing tests to tell Computers and Humans Apart (CAPTCHAs), the CAPTCHA using mental rotation has been proposed. Mental rotation is an advanced human-cognitiveprocessing ability to rotate mental representations of “one” single 2D/3D object. However, as have already been reported, the mental rotation CAPTCHA can be overcome by pattern matching a...

Phishing is an attempt by an individual or a group to thieve personal confidential information such as passwords, credit card information etc from unsuspecting victims for identity theft, financial gain and other fraudulent activities. In this paper we have proposed a new approach named as "A Novel Antiphishing framework based on visual cryptography" to solve the problem of phishing. Here an im...

Abstract: CAPTCHA-Systeme sind weit verbreitete Schutzsysteme, um auf OnlinePlattformen menschliche Benutzer von automatischen Bots zu unterscheiden. Dabei kommen verschiedene Varianten zum Einsatz, die sich in Art und Interaktionsmodus sowie im Schwierigkeitsgrad der Lösung unterscheiden. In der vorliegenden Studie werden Kriterien der Benutzbarkeit von CAPTCHA-Systemen aufgestellt. Zudem werd...

In this paper we present a new CAPTCHA system (Completely Automated Turing Test To Tell Computers and Humans Apart). This proposal, SemCAPTCHA, is motivated by an increasing number of broken OCR-based CAPTCHA systems and it is based not only on text recognition but also on text understanding. We describe SemCAPTCHA from both user’s perspective and system’s perspective and compare it to some cur...

The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) technique has been an interesting topic for several years. An Arabic CAPTCHA recently proposed serve Arab users. Since there have few scientific studies supporting a systematic design or tuning users, this paper aims analyze the text-based at parameter level by conducting experimental study. Based on result...

There is clearly a need on the web for security features to stop spam and bots. However, many security features on web sites are not accessible for people with disabilities. A common form of security on web sites is a human interaction proof. HIPs are used to differentiate between humans and automated bots. The most common form of HIP is known as a CAPTCHA (Completely Automated Public Turing te...

In this paper we present a new CAPTCHA system (Completely Automated Turing Test To Tell Computers and Humans Apart). The proposal of SemCAPTCHA is motivated by an increasing number of broken OCR-based CAPTCHA systems and it is based not only on text recognition but also on text understanding. We describe both, the user’s and the system’s perspective of SemCAPTCHA and compare it with some curren...

We argue that a set of usability heuristics are needed for easy and quick evaluation of Captchas implementations. With this set of heuristics we contribute to sustain the Captcha Mantra: “Easy for humans, hard for machines”. In particular, the usability of Captcha schemes change radically when utilized on mobile environments. We are developing a set of heuristics for use by practitioners wishin...