Does counting still count? Revisiting the security of counting based user authentication protocols against statistical attacks

At NDSS 2012, Yan et al. analyzed the security of several challenge-response type user authentication protocols against passive observers, and proposed a generic counting based statistical attack to recover the secret of some counting based protocols given a number of observed authentication sessions. Roughly speaking, the attack is based on the fact that secret (pass) objects appear in challenges with a different probability from non-secret (decoy) objects when the responses are taken into account. Although they mentioned that a protocol susceptible to this attack should minimize this difference, they did not give details as to how this can be achieved barring a few suggestions. In this paper, we attempt to fill this gap by generalizing the attack with a much more comprehensive theoretical analysis. Our treatment is more quantitative which enables us to describe a method to theoretically estimate a lower bound on the number of sessions a protocol can be safely used against the attack. Our results include 1) two proposed fixes to make counting protocols practically safe against the attack at the cost of usability, 2) the observation that the attack can be used on non-counting based protocols too as long as challenge generation is contrived, 3) and two main design principles for user authentication protocols which can be considered as extensions of the principles from Yan et al. This detailed theoretical treatment can be used as a guideline during the design of counting based protocols to determine their susceptibility to this attack. The Foxtail protocol, one of the protocols analyzed by Yan et al., is used as a representative to illustrate our theoretical and experimental results.

Database relation watermarking resilient against secondary watermarking attacks

There has been tremendous interest in watermarking multimedia content during the past two decades, mainly for proving ownership and detecting tamper. Digital fingerprinting, that deals with identifying malicious user(s), has also received significant attention. While extensive work has been carried out in watermarking of images, other multimedia objects still have enormous research potential. Watermarking database relations is one of the several areas which demand research focus owing to the commercial implications of database theft. Recently, there has been little progress in database watermarking, with most of the watermarking schemes modeled after the irreversible database watermarking scheme proposed by Agrawal and Kiernan. Reversibility is the ability to re-generate the original (unmarked) relation from the watermarked relation using a secret key. As explained in our paper, reversible watermarking schemes provide greater security against secondary watermarking attacks, where an attacker watermarks an already marked relation in an attempt to erase the original watermark. This paper proposes an improvement over the reversible and blind watermarking scheme presented in [5], identifying and eliminating a critical problem with the previous model. Experiments showing that the average watermark detection rate is around 91% even with attacker distorting half of the attributes. The current scheme provides security against secondary watermarking attacks.

Geometric sensitivity of patient-specific finite element models of the spine to variability in user-selected anatomical landmarks

Software to create individualised finite element (FE) models of the osseoligamentous spine using pre-operative computed tomography (CT) data-sets for spinal surgery patients has recently been developed. This study presents a geometric sensitivity analysis of this software to assess the effect of intra-observer variability in user-selected anatomical landmarks. User-selected landmarks on the osseous anatomy were defined from CT data-sets for three scoliosis patients and these landmarks were used to reconstruct patient-specific anatomy of the spine and ribcage using parametric descriptions. The intra-observer errors in landmark co-ordinates for these anatomical landmarks were calculated. FE models of the spine and ribcage were created using the reconstructed anatomy for each patient and these models were analysed for a loadcase simulating clinical flexibility assessment. The intra-observer error in the anatomical measurements was low in comparison to the initial dimensions, with the exception of the angular measurements for disc wedge and zygapophyseal joint (z-joint) orientation and disc height. This variability suggested that CT resolution may influence such angular measurements, particularly for small anatomical features, such as the z-joints, and may also affect disc height. The results of the FE analysis showed low variation in the model predictions for spinal curvature with the mean intra-observer variability substantially less than the accepted error in clinical measurement. These findings demonstrate that intra-observer variability in landmark point selection has minimal effect on the subsequent FE predictions for a clinical loadcase.

From impact assessment to user-friendly risk management decision-making

In earlier cultures and societies, hazards and risks to human health were dealt with by methods derived from myth, metaphor and ritual. In modem society however, notions of hazard and risk have been transformed from the level of a folk discourse to that of an expert centred concept (Plough & Krimsky, 1987). With the professionalization of risk and hazard analysis came a preferred framework for decision making based on a range of 'technical' methodologies (Giere, 1991 ). This is especially true for decision processes relating to risk assessment and management, and impact assessment. Such approaches however, often entail narrow technical-based theoretical assumptions about human behaviour and the natural world, and the· methods used. They therefore carry 'in-built' error factors that contribute considerable uncertainty to the results.

Semantic querying of business process models

Determining similarity between business process models has recently gained interest in the business process management community. So far similarity was addressed separately either at semantic or structural aspect of process models. Also, most of the contributions that measure similarity of process models assume an ideal case when process models are enriched with semantics - a description of meaning of process model elements. However, in real life this results in a heavy human effort consuming pre-processing phase which is often not feasible. In this paper we propose an automated approach for querying a business process model repository for structurally and semantically relevant models. Similar to the search on the Internet, a user formulates a BPMN-Q query and as a result receives a list of process models ordered by relevance to the query. We provide a business process model search engine implementation for evaluation of the proposed approach.

Histories of user-generated content : between formal and informal media economies

Debates about user-generated content (UGC) often depend on a contrast with its normative opposite, the professionally produced content that is supported and sustained by commercial media businesses or public organisations. UGC is seen to appear within or in opposition to professional media, often as a disruptive, creative, change-making force. Our suggestion is to position UGC not in opposition to professional or "producer media", or in hybridised forms of subjective combination with it (the so-called "pro-sumer" or "pro-am" system), but in relation to different criteria, namely the formal and informal elements in media industries. In this article, we set out a framework for the comparative and historical analysis of UGC systems and their relations with other formal and informal media activity, illustrated with examples ranging from games to talkback radio. We also consider the policy implications that emerge from a historicised reading of UGC as a recurring dynamic within media industries, rather than a manifestation of consumer agency specific to digital cultures.

When should private property rights give way to the public interest?

Since Queensland Wire Industries Pty Ltd v Broken Hill Pty Co Ltd (1989) 167 CLR 177 it has been recognised that corporations with substantial market power are subject to special responsibilities and restraints that corporations without market power are not. In NT Power Generation Pty Ltd v Power and Water Authority (2004) 219 CLR 90 McHugh A-CJ, Gummow, Callinan and Heydon JJ in their joint reasons stated (at [76]), that s 46 of the Competition and Consumer Act 2010 (Cth) (CCA) can operate not only to prevent firms with substantial market power from doing prohibited things, but also compel them positively to do things they do not want to do. Their Honours also stated (at [126]) that the proposition that a private property owner who declines to permit competitors to use the property is immune from s 46 is “intrinsically unsound”. However, the circumstances in which a firm with substantial power must accommodate competitors, and private property rights give way to the public interest are uncertain. The purpose of this Note is to consider recent developments in two areas of the CCA where the law requires private property rights to give way to the public interest. The first part of the Note considers two recent cases which clarify the circumstances in which s 46 of the CCA can be used to compel a firm with substantial market power to accommodate a competitor and allow the competitor to make use of private property rights in the public interest. Secondly, on 12 February 2014 the Minister for Small Business, the Hon Bruce Billson,released the Productivity Commission’s Final Report, on the National Access Regime in Pt IIIA of the CCA (National Access Regime, Inquiry Report No 66, Canberra). Pt IIIA provides for the processes by which third parties may obtain access to infrastructure owned by others in the public interest. The Report recommends that Pt IIIA be retained but makes a number of suggestions for its reform, some of which will be briefly considered.

Experience as meaning : some underlying concepts and implications for design

As the current computing systems move from desktop and work settings into our everyday lives (e.g. mobile and ubiquitous systems) a growing interest is seen for designing interactive systems with experiential support. Some conceptual work already exists that tries to analyze and understand users? experience with interactive systems but in practice this is still not frequently used. Drawing on the concepts from the domain of art, this paper introduces a way to conceptualize users? experience as the meanings or interpretations they construct during their interaction with or through the interactive systems. We consequently apply this conceptualization in a design project where we use it at an early concept design stage for designing aware technologies in care-taking situations.

Aspect-based model of user experience

Traditional HCI design and evaluation methods merely focus on functional and usability aspects of a product. Although these aspects are important, they do not guarantee product’s success, especially the consumer product. Many consumer products are now part of user’s everyday activities – that support fun, pleasure, entertainment, etc. Secondly, in today’s consumer market many of the products have become similar in terms of their technology, functionality, price and quality. In response, many companies have started designing products with added emotional and experiential values. This has challenged designer’s to explore and visualize directions in product design field that could evoke intended and desired experiences amongst its users. Subjective product qualities such as fun, pleasure, entertainment, etc. are not the part of a product, but they are better thought of as the outcome of user’s interaction with the product...

Measuring Online user engagement : the limitations of Web analytics

The ability to identify and assess user engagement with transmedia productions is vital to the success of individual projects and the sustainability of this mode of media production as a whole. It is essential that industry players have access to tools and methodologies that offer the most complete and accurate picture of how audiences/users engage with their productions and which assets generate the most valuable returns of investment. Drawing upon research conducted with Hoodlum Entertainment, a Brisbane-based transmedia producer, this chapter outlines an initial assessment of the way engagement tends to be understood, why standard web analytics tools are ill-suited to measuring it, how a customised tool could offer solutions, and why this question of measuring engagement is so vital to the future of transmedia as a sustainable industry.

Formation of neutral molecules of potential stellar interest by neutralisation of negative ions in a mass spectrometer - The application of experiment and molecular modelling in concert

This paper is a modified version of a lecture which describes the synthesis, structure and reactivity of some neutral molecules of stellar significance. The neutrals are formed in the collision cell of a mass spectrometer following vertical Franck-Condon one electron oxidation of anions of known bond connectivity. Neutrals are characterised by conversion to positive ions and by extensive theoretical studies at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31G(d) level of theory. Four systems are considered in detail, viz (i) the formation of linear C-4 and its conversion to the rhombus C-4, (ii) linear C-5 and the atom scrambling of this system when energised, (iii) the stable cumulene oxide CCCCCO, and (iv) the elusive species O2C-CO. This paper is not intended to be a review of interstellar chemistry: examples are selected from our own work in this area. (C) 2002 Elsevier Science Inc. All rights reserved.

Mandatory offers under the Motor Accident Insurance Act 1994 - with interest please!

In Windon v Edwards [2005] QDC 029 Robin QC DCJ considered the cost consequence of mandatory final offers under the Motor Accident Insurance Act 1994 (Qld)

Supreme Court Act 1995 s48 - Interest on judgment for damages for personal injuries

The case of Flynn v The Maryborough Sugar Factory Limited [2003] QDC 446 the plaintiff had been awarded damages for personal injuries and there was a charge on those damages under a Commonwealth statute, with a provision in the statute that damages could not be satisfied until the Commonwealth had been paid. The Court considered the point of considerable practical significance of whether interest accrued on the judgment under s48 of the Supreme Court Act 1995 (Qld) before the defendant had obtained clearances under the Commonwealth legislation.

Damages for personal injuries in Queensland : interest please!

The article revises established principles relating to the awarding of damages to the date of judgment and discusses decisions in the High Court and in the Supreme Court of Queensland which have caused significant changes to the manner of assessments of interest. Its purpose is to provide for practitioners involved in personal injuries litigation in Queensland a current set of guidelines as to the manner in which the wide discretion to award interest may be expected to be exercised.

The duty to report disease outbreaks : of interest or value? Lessons from H5N1

Since the severe acute respiratory syndrome outbreak in 2003, it has been argued that there has been a substantial revision to the norm dictating the behaviour of states in the event of a disease outbreak. This article examines the evolution of the norm to ‘report and verify’ disease outbreaks and evaluates the extent to which this revised norm has begun to guide state behaviour. Examination of select East Asian countries affected by human infections of the H5N1 (avian influenza) virus strain reveals the need to further understand the mutually constitutive relationship between the value attached to prompt reporting against the capacity to report, and how states manage both in fulfilling their duty to report.