6,502 research outputs found
Privacy and Usability of Image and Text Based Challenge Questions Authentication in Online Examination
In many online examinations, physical invigilation is often replaced with traditional authentication approaches for student identification. Secure and usable authentication approaches are important for high stake online examinations. A Profile Based Authentication Framework (PBAF) was developed and implemented in a real online learning course embedded with summative online examination. Based on usersâ experience of using the PBAF in an online course, online questionnaires were used to collect participants' feedback on effectiveness, layout and appearance, user satisfaction, distraction and privacy concerns. Based on overall findings of the quantitative analysis, there was a positive feedback on the use of a hybrid approach utilizing image and text based challenge questions for better usability. However, the number of questions presented during learning and examination processes were reported to be too many and caused distraction. Participants expressed a degree of concern on sharing personal and academic information with little or no privacy concern on using favorite question
Leveraging OpenStack and Ceph for a Controlled-Access Data Cloud
While traditional HPC has and continues to satisfy most workflows, a new
generation of researchers has emerged looking for sophisticated, scalable,
on-demand, and self-service control of compute infrastructure in a cloud-like
environment. Many also seek safe harbors to operate on or store sensitive
and/or controlled-access data in a high capacity environment.
To cater to these modern users, the Minnesota Supercomputing Institute
designed and deployed Stratus, a locally-hosted cloud environment powered by
the OpenStack platform, and backed by Ceph storage. The subscription-based
service complements existing HPC systems by satisfying the following unmet
needs of our users: a) on-demand availability of compute resources, b)
long-running jobs (i.e., days), c) container-based computing with
Docker, and d) adequate security controls to comply with controlled-access data
requirements.
This document provides an in-depth look at the design of Stratus with respect
to security and compliance with the NIH's controlled-access data policy.
Emphasis is placed on lessons learned while integrating OpenStack and Ceph
features into a so-called "walled garden", and how those technologies
influenced the security design. Many features of Stratus, including tiered
secure storage with the introduction of a controlled-access data "cache",
fault-tolerant live-migrations, and fully integrated two-factor authentication,
depend on recent OpenStack and Ceph features.Comment: 7 pages, 5 figures, PEARC '18: Practice and Experience in Advanced
Research Computing, July 22--26, 2018, Pittsburgh, PA, US
Print-Scan Resilient Text Image Watermarking Based on Stroke Direction Modulation for Chinese Document Authentication
Print-scan resilient watermarking has emerged as an attractive way for document security. This paper proposes an stroke direction modulation technique for watermarking in Chinese text images. The watermark produced by the idea offers robustness to print-photocopy-scan, yet provides relatively high embedding capacity without losing the transparency. During the embedding phase, the angle of rotatable strokes are quantized to embed the bits. This requires several stages of preprocessing, including stroke generation, junction searching, rotatable stroke decision and character partition. Moreover, shuffling is applied to equalize the uneven embedding capacity. For the data detection, denoising and deskewing mechanisms are used to compensate for the distortions induced by hardcopy. Experimental results show that our technique attains high detection accuracy against distortions resulting from print-scan operations, good quality photocopies and benign attacks in accord with the future goal of soft authentication
Watermarking Using Decimal Sequences
This paper introduces the use of decimal sequences in a code division
multiple access (CDMA) based watermarking system to hide information for
authentication in black and white images. Matlab version 6.5 was used to
implement the algorithms discussed in this paper. The advantage of using
d-sequences over PN sequences is that one can choose from a variety of prime
numbers which provides a more flexible system.Comment: 8 pages, 9 figure
Improving random number generators by chaotic iterations. Application in data hiding
In this paper, a new pseudo-random number generator (PRNG) based on chaotic
iterations is proposed. This method also combines the digits of two XORshifts
PRNGs. The statistical properties of this new generator are improved: the
generated sequences can pass all the DieHARD statistical test suite. In
addition, this generator behaves chaotically, as defined by Devaney. This makes
our generator suitable for cryptographic applications. An illustration in the
field of data hiding is presented and the robustness of the obtained data
hiding algorithm against attacks is evaluated.Comment: 6 pages, 8 figures, In ICCASM 2010, Int. Conf. on Computer
Application and System Modeling, Taiyuan, China, pages ***--***, October 201
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