Smartphones play an important role in the information-communication society and accesses from smartphones to the Internet services increase more and more with the advent of cloud computing. Smartphones have comparatively small displays and it is possible for users to input data through touchscreens. The techniques such as a CAPTCHA (Completely Automated Public Turing test to tell Computers and ...

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 ...

Information and computer security is supported by passwords. Password is the principal part of authentication process. The traditional authentication method is to use text-based password which is also called alphanumeric password. But it has significant drawbacks. So to overcome vulnerabilities of this traditional password scheme a graphical password scheme is developed. But major drawback of g...

-We are in the era of internet and depend on it for every necessary requirement. It is the tendency of the some human to have destructive approach rather than having constructive approach. Among the abuse and misuse of internet, the distributed denial of service attack (DDOS) is the most hectic one. People have carried out various method of mitigation using the CAPTCHA (Completely Automated Pub...

The advent of mobile devices and media cloud services has led to the unprecedented growth of personal photo collections. One of the fundamental problems in managing the increasing number of photos is automatic image tagging. Image tagging is the task of assigning human-friendly tags to an image so that the semantic tags can better reflect the content of the image and therefore can help users be...

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...

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. In this paper, we present a new security primitive based on hard AI problems, namely, a novel family of graph-ical password systems built on top of Captcha technology, which we call Captcha as graphical passwords (CaRP). CaRP...

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...

CAPTCHA is widely used security technique employed to avoid automated form submissions or verify user as human. An alternative CAPTCHA method based on pattern matching and number recognition ability is proposed in this paper, which verifies user as human and prevents bots to intervene and spam applications or services. This method is based on user gestures which make it unique and secure. The b...

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...