322 research outputs found
CAPTCHaStar! A novel CAPTCHA based on interactive shape discovery
Over the last years, most websites on which users can register (e.g., email
providers and social networks) adopted CAPTCHAs (Completely Automated Public
Turing test to tell Computers and Humans Apart) as a countermeasure against
automated attacks. The battle of wits between designers and attackers of
CAPTCHAs led to current ones being annoying and hard to solve for users, while
still being vulnerable to automated attacks.
In this paper, we propose CAPTCHaStar, a new image-based CAPTCHA that relies
on user interaction. This novel CAPTCHA leverages the innate human ability to
recognize shapes in a confused environment. We assess the effectiveness of our
proposal for the two key aspects for CAPTCHAs, i.e., usability, and resiliency
to automated attacks. In particular, we evaluated the usability, carrying out a
thorough user study, and we tested the resiliency of our proposal against
several types of automated attacks: traditional ones; designed ad-hoc for our
proposal; and based on machine learning. Compared to the state of the art, our
proposal is more user friendly (e.g., only some 35% of the users prefer current
solutions, such as text-based CAPTCHAs) and more resilient to automated
attacks.Comment: 15 page
Designing Mobile Friendly CAPTCHAs: An Exploratory Study.
CAPTCHAs (Completely Automated Public Turing Test to Tell Computers and Humans Apart) are one of the most widely used authentication mechanisms that help to prevent online service abuse. With the advent of mobile computing, mobile devices such as smartphones and tablets have become the primary way people access the Internet. As a result, increasing attention has been paid to designing CAPTCHAs that are mobile friendly. Although such CAPTCHAs generally show their advantages over traditional ones, it is still unclear what the best practices are for designing a CAPTCHA scheme that is easy to use on mobile devices. In this paper, we present an exploratory study that focuses on developing a more holistic view of usability issues with interactive CAPTCHAs to inform design guidance. This is done through investigating the usability performance of seven mobile friendly CAPTCHA schemes representing five different CAPTCHA types
CAPTCHA Types and Breaking Techniques: Design Issues, Challenges, and Future Research Directions
The proliferation of the Internet and mobile devices has resulted in
malicious bots access to genuine resources and data. Bots may instigate
phishing, unauthorized access, denial-of-service, and spoofing attacks to
mention a few. Authentication and testing mechanisms to verify the end-users
and prohibit malicious programs from infiltrating the services and data are
strong defense systems against malicious bots. Completely Automated Public
Turing test to tell Computers and Humans Apart (CAPTCHA) is an authentication
process to confirm that the user is a human hence, access is granted. This
paper provides an in-depth survey on CAPTCHAs and focuses on two main things:
(1) a detailed discussion on various CAPTCHA types along with their advantages,
disadvantages, and design recommendations, and (2) an in-depth analysis of
different CAPTCHA breaking techniques. The survey is based on over two hundred
studies on the subject matter conducted since 2003 to date. The analysis
reinforces the need to design more attack-resistant CAPTCHAs while keeping
their usability intact. The paper also highlights the design challenges and
open issues related to CAPTCHAs. Furthermore, it also provides useful
recommendations for breaking CAPTCHAs
Loyalty cards and the problem of CAPTCHA: 2nd tier security and usability issues for senior citizens
Information Security often works in antipathy to access and useability in communities of older citizens. Whilst security features are required to prevent the disclosure of information, some security tools have a deleterious effect upon users, resulting in insecure practices. Security becomes unfit for purpose where users prefer to abandon applications and online benefits in favour of non-digital authentication and verification requirements. For some, the ability to read letters and symbols from a distorted image is a decidedly more difficult task than for others, and the resulting level of security from CAPTCHA tests is not consistent from person to person. This paper discusses the changing paradigm regarding second tier applications where non-essential benefits are forgone in order to avoid the frustration, uncertainty and humiliation of repeated failed attempts to access online software by means of CAPTCHA
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