Physical Sciences and Mathematics Commons^™

Identity-Based Traitor Tracing With Short Private Key And Short Ciphertext, Fuchun Guo, Yi Mu, Willy Susilo

Professor Willy Susilo

Identity-based traitor tracing (IBTT) scheme can be utilized to identify a private (decryption) key of any identity that is illegally used in an identity-based broadcast encryption scheme. In PKC'07, Abdalla et al. proposed the first IBTT construction with short private key. In CCS'08, Boneh and Naor proposed a public-key traitor tracing, which can be extended to IBTT with short ciphertext. With a further exploration, in this paper, we propose the first IBTT with short private key and short ciphertext. Private key and ciphertext are both order of O(l 1+l 2), where l 1 is the bit length of codeword of …

Sefap: An Email System For Anti-Phishing, Qoing Ren, Yi Mu, Willy Susilo

Professor Willy Susilo

More and more users are suffering from email-based phishing attacks over the past years. Despite the use of various technologies for anti-phishing, phishing is still one of most serious attacks against Internet users. Email phishing attacks fabricate the email’s origin. Unfortunately, current email server systems can not authenticate the genuineness of in-coming emails. In this paper, we present a novel antiphishing mechanism: Signed Email for Anti-Phishing (SEFAP), designed to automatically identify an email’s origin to mitigate email phishing attacks. The SEFAP system is an extendable secure cryptographic system that accommodates multiple signature schemes. SEFAP can adopt any signature scheme which …

Security Analysis Of Michael: The Ieee 802.11i Message Integrity Code, Jianyong Huang, Jennifer Seberry, Willy Susilo, Martin W. Bunder

Professor Willy Susilo

The latest IEEE 802.11i uses a keyed hash function, called Michael, as the message integrity code. This paper describes some properties and weaknesses of Michael. We provide a necessary and sufficient condition for finding collisions of Michael. Our observation reveals that the collision status of Michael only depends on the second last block message and the output of the block function in the third last round. We show that Michael is not collision-free by providing a method to find collisions of this keyed hash function. Moreover, we develop a method to find fixed points of Michael. If the output of …

Efficient And Secure Stored-Value Cards With Leakage Resilience, Fuchun Guo, Yi Mu, Willy Susilo

Professor Willy Susilo

Stored-value cards (SVCs) are a kind of smartcards that can be used to store monetary values. SVCs have demonstrated a wide range of applications in commerce. SVCs are in general tamper-resistant, but they are very computationally weak and their security mechanisms are also weak against side-channel attacks. In this paper, we propose an efficient and secure stored-value card system. With the help of pre-computations, storedvalue cards in our scheme are only required to perform simple arithmetic operations and bitwise comparisons. Our system especially for SVCs is secure with unbounded computational leakage resilience. Our novel scheme provides a practical solution to …

Cryptanalysis On Two Certificateless Signature Schemes, Futai Zhang, Sujuan Li, Songqin Miao, Yi Mu, Willy Susilo, Xinyi Huang

Professor Willy Susilo

Certificateless cryptography [1] is a new paradigm that not only removes the inherent key escrow problem of identity based public cryptography [2] (ID-PKC for short), but also eliminates the cumbersome certificate management in traditional PKI. In CL-PKC, the actual private key of a user is comprised of two secrets: a secret value and a partial private key. The user generates a secret value by himself, while the partial private key is generated by a third party called Key Generating Center (KGC), who makes use of a system wide master key and the user’s identity information. In this way, the key …

A Provable Secure Id-Based Explicit Authenticated Key Agreement Protocol Without Random Oracles, Haibo Tian, Willy Susilo, Yang Ming, Yumin Wang

Professor Willy Susilo

In this paper, we present an identity-based explicit authenticated key agreement protocol that is provably secure without random oracles. The protocol employs a new method to isolate a session key from key con¯rmation keys so that there is no direct usage of hash functions in the protocol. The protocol is proved secure without random oracles in a variant of Bellare and Rogaway style model, an exception to current proof method in this style model in the ID-based setting. We believe that this key isolation method is novel and can be further studied for constructing more e±cient protocols.

Enhancing The Perceived Visual Quality Of A Size Invariant Visual Cryptography Scheme, Yang-Wai Chow, Willy Susilo, Duncan S Wong

Professor Willy Susilo

Two of the main areas of research in visual cryptography have been on improving the visual quality of the recovered image and in reducing the pixel expansion of the shares. This paper addresses both of these visual cryptography issues. First, a method to enhance the perceived visual quality of the recovered image using various image filtering techniques is presented. In particular, these image filtering techniques are used to enhance the local and global contrasts of a grayscale image. Second, a multi-pixel block size invariant visual cryptography scheme that maintains the relative density of local neighboring pixels is proposed. This method …

Short E-Cash, Man Ho Au, Sherman S. M. Chow, Willy Susilo

Professor Willy Susilo

We present a bandwidth-efficient off-line anonymous e-cash scheme with traceable coins. Once a user double-spends, his identity can be revealed and all his coins in the system can be traced, without resorting to TTP. For a security level comparable with 1024-bit standard RSA signature, the payment transcript size is only 512 bytes. Security of the proposed scheme is proven under the q-strong Diffie-Hellman assumption and the decisional linear assumption, in the random oracle model. The transcript size of our scheme can be further reduced to 192 bytes if external Diffie-Hellman assumption is made. Finally, we propose a variant such that …

Blacr: Ttp-Free Blacklistable Anonymous Credentials With Reputation, Man Ho Au, Apu Kapadia, Willy Susilo

Professor Willy Susilo

Anonymous authentication can give users the license to misbehave since there is no fear of retribution. As a deterrent, or means to revocation, various schemes for accountable anonymity feature some kind of (possibly distributed) trusted third party (TTP) with the power to identify or link misbehaving users. Recently, schemes such as BLAC and PEREA showed how anonymous revocation can be achieved without such TTPs—anonymous users can be revoked if they misbehave, and yet nobody can identify or link such users cryptographically. Despite being the state of the art in anonymous revocation, these schemes allow only a basic form of revocation …

Efficient Strong Designated Verifier Signature Schemes Without Random Oracle Or With Non-Delegatability, Q Huang, G Yang, D S Wong, Willy Susilo

Professor Willy Susilo

Designated verifier signature (DVS) allows a signer to convince a designated verifier that a signature is generated by the signer without letting the verifier transfer the conviction to others, while the public can still tell that the signature must be generated by one of them. Strong DVS (SDVS) strengthens the latter part by restricting the public from tellingwhether the signature is generated by one of them or by someone else. In this paper, we propose two new SDVS schemes. Compared with existing SDVS schemes, the first new scheme has almost the same signature size and meanwhile, is proven secure in …

Attribute-Based Oblivious Access Control, Jinguang Han, Willy Susilo, Yi Mu, Jun Yan

Professor Willy Susilo

In an attribute-based system (ABS), users are identified by various attributes, instead of their identities. Since its seminal introduction, the attribute-based mechanism has attracted a lot of attention. However, current ABS schemes have a number of drawbacks: (i) the communication cost is linear in the number of the required attributes; (ii) the computation cost is linear in the number of the required attributes and (iii) there are no efficient verification algorithms for the secret keys. These drawbacks limit the use of ABS in practice. In this paper, we propose an attribute-based oblivious access control (ABOAC) scheme to address these problems, …

Analysis Of Property-Preservation Capabilities Of The Rox And Esh Hash Domain Extenders, Reza Reyhanitabar, Willy Susilo, Yi Mu

Professor Willy Susilo

Two of the most recent and powerful multi-property preserving (MPP) hash domain extension transforms are the Ramdom-Oracle-XOR (ROX) transform and the Enveloped Shoup (ESh) transform. The former was proposed by Andreeva et al. at ASIACRYPT 2007 and the latter was proposed by Bellare and Ristenpart at ICALP 2007. In the existing literature, ten notions of security for hash functions have been considered in analysis of MPP capabilities of domain extension transforms, namely CR, Sec, aSec, eSec (TCR), Pre, aPre, ePre, MAC, PRF, PRO. Andreeva et al. showed that ROX is able to preserve seven properties; namely collision resistance (CR), three …

Reaction Attack On Outsourced Computing With Fully Homomorphic Encryption Schemes, Zhenfei Zhang, Thomas Plantard, Willy Susilo

Professor Willy Susilo

Outsourced computations enable more efficient solutions towards practical problems that require major computations. Nevertheless, users’ privacy remains as a major challenge, as the service provider can access users’ data freely. It has been shown that fully homomorphic encryption schemes might be the perfect solution, as it allows one party to process users’ data homomorphically, without the necessity of knowing the corresponding secret keys. In this paper, we show a reaction attack against full homomorphic schemes, when they are used for securing outsourced computation. Essentially, our attack is based on the users’ reaction towards the output generated by the cloud. Our …

The Analysis Of Stratified Multiple Responses, Ivy Liu, Thomas Suesse

Dr Thomas Suesse

Surveys often contain qualitative variables for which respondents may select any number of the outcome categories. For instance, for the question “What type of contraception have you used?” with possible responses (oral, condom, lubricated condom, spermicide, and diaphragm), respondents would be instructed to select as many of the outcomes that apply. This situation is known as multiple responses. When the data includes stratification variables, we discuss two approaches: (1) the “GEE” approach which uses logit models directly applying the generalized estimating equations (GEE) method (Liang and Zeger, 1986); and (2) the “GMH” approach which extends the generalized Mantel–Haenszel type estimators …

Methods For Parameter Identification In Oscillatory Networks And Application To Cortical And Thalamic 600 Hz Activity, Thomas Suesse, Jens Haueisen, Lutz Leistritz, Herbert Witte, Bernd Hilgenfeld

Dr Thomas Suesse

No abstract provided.

Person-Level And Household-Level Regression Estimation In Household Surveys, David G. Steel, Robert Graham Clark

Professor David Steel

A common class of survey designs involves selecting all people within selected households. Generalized regressionestimators can be calculated at either the person or household level. Implementing the estimator at the household level has the convenience of equal estimation weights for people within households. In this article the two approaches are compared theoretically and empirically for the case of simple random sampling of households and selection of all persons in each selected household. We find that the household level approach is theoretically more efficient in large samples and any empirical inefficiency in small samples is limited.

The 2003 Australian Breast Health Survey: Survey Design And Preliminary Results, Elmer V. Villanueva, Sandra C. Jones, Caroline Nehill, Simone K. Favelle, David G. Steel, Don Iverson, Helen Zorbas

Professor David Steel

The Breast Health Surveys, conducted by the National Breast Cancer Centre (NBCC) in 1996 and 2003, are designed to gain insight into the knowledge, attitudes and behaviours of a nationally representative sample of Australian women on issues relevant to breast cancer. In this article, we focus on major aspects of the design and present results on respondents' knowledge about mammographic screening. Methods: The 2003 BHS surveyed English-speaking Australian women aged 3069 without a history of breast cancer using computer-assisted telephone interviewing. Questions covered the following themes: knowledge and perceptions about incidence, mortality and risk; knowledge and behaviour regarding early detection, …

Contextual Effects In Modeling For Small Domain Estimation, Mohammad-Reza Namazi-Rad, David G. Steel

Professor David Steel

Many different Small Area Estimation (SAE) methods have been proposed to overcome the challenge of findingreliable estimates for small domains. Often, the required data for various research purposes are available at differentlevels of aggregation. Based on the available data, individual-level or aggregated-level models are used in SAE.However, parameter estimates obtained from individual and aggregated level analysis may be different, in practice.This may happen due to some substantial contextual or area-level effects in the covariates which may be misspecifiedin individual-level analysis. If small area models are going to be interpretable in practice, possible contextualeffects should be included. Ignoring these effects leads …

Understanding Ageing In Older Australians: The Contribution Of The Dynamic Analyses To Optimise Ageing (Dynopta) Project To The Evidence Base And Policy, Kaarin Anstey, Allison Blelak, Carole Birrell, Colette Browning, Richard Burns, Julie Byles, Kim Kiely, Binod Nepal, Lesley Ross, David Steel, Timothy Windsor

Professor David Steel

Aim:  To describe the Dynamic Analyses to Optimise Ageing (DYNOPTA) project and illustrate its contributions to understanding ageing through innovative methodology, and investigations on outcomes based on the project themes. DYNOPTA provides a platform and technical expertise that may be used to combine other national and international datasets. Methods:  The DYNOPTA project has pooled and harmonised data from nine Australian longitudinal studies to create the largest available longitudinal dataset (n= 50652) on ageing in Australia. Results:  A range of findings have resulted from the study to date, including methodological advances, prevalence rates of disease and disability, and mapping trajectories of …

Multistage Sampling, David Steel

Professor David Steel

No abstract provided.

Estimates Of Probable Dementia Prevalence From Population-Based Surveys Compared With Dementia Prevalence Estimates Based On Meta-Analyses, Kaarin J. Anstey, Richard A. Burns, Carole Birrell, David G. Steel, Kim M. Kiely, Mary A. Luszcz

Professor David Steel

Background: National data on dementia prevalence are not always available, yet it may be possible to obtain estimates from large surveys that include dementia screening instruments. In Australia, many of the dementia prevalence estimates are based on European data collected between 15 and 50 years ago. We derived populationbased estimates of probable dementia and possible cognitive impairment in Australian studies using the Mini-Mental State Examination (MMSE), and compared these to estimates of dementia prevalence from meta-analyses of European studies.

Methods: Data sources included a pooled dataset of Australian longitudinal studies (DYNOPTA), and two Australian Bureau of Statistics National …

Measuring And Analyzing The Within Group Homogeneity Of Multi-Category Variables, David Steel, Mark Tranmer

Professor David Steel

No abstract provided.

Unravelling Ecological Analysis, David Steel, Mark Tranmer, D Holt

Professor David Steel

No abstract provided.

Accounting For The Uncertainty Of Information On Clustering In The Design Of A Clustered Sample, David G. Steel, Robert Graham Clark

Professor David Steel

An important decision that has to be made in developing the design of a cluster or multi-stage sampling scheme is the number of units to select at each stage of selection. For a two-stage design we need to decide the number of units to select from each Primary Sampling Unit (PSU) in the sample. A common approach is to estimate the costs and the variance components associated with each stage of selection and determine an optimal design. This is usually done for estimates of the means or totals of one or a small number of variables. In practice the measure …

Investigation Of Relative Risk Estimates From Studies Of The Same Population With Contrasting Response Rates And Designs, Nicole M. Mealing, Emily Banks, Louisa R. Jorm, David G. Steel, Mark S. Clements, Kris D. Rogers

Professor David Steel

Background: There is little empirical evidence regarding the generalisability of relative risk estimates from studies which have relatively low response rates or are of limited representativeness. The aim of this study was to investigate variation in exposure-outcome relationships in studies of the same population with different response rates and designs by comparing estimates from the 45 and Up Study, a population-based cohort study (self-administered postal questionnaire, response rate 18%), and the New South Wales Population Health Survey (PHS) (computer-assisted telephone interview, response rate ~60%). Methods: Logistic regression analysis of questionnaire data from 45 and Up Study participants (n = 101,812) …

Seasonal Adjustment Of An Aggregate Series Using Univariate And Multivariate Basic Structural Models, David Steel, Yan-Xia Lin, Carole Birrell

Professor David Steel

Time series resulting from aggregation of several sub-series can be seasonally adjusted directlyor indirectly. With model-based seasonal adjustment, the sub-series may also be considered as amultivariate system of series and the analysis may be done jointly. This approach has considerableadvantage over the indirect method, as it utilises the covariance structure between the sub-series.This paper compares a model-based univariate and multivariate approach to seasonal adjustment.Firstly, the univariate basic structural model (BSM) is applied directly to the aggregate series. Secondly,the multivariate BSM is applied to a transformed system of sub-series. The prediction meansquared errors of the seasonally adjusted aggregate series resulting from …

Application Of Multi-Phase Experiments In Plant Pathology To Identify Genetic Resistance To Diaporthe Toxica In Lupinus Albus, R. B. Cowley, G. J. Ash, J. D. I. Harper, Alison Smith, Brian Cullis, D. J. Luckett

Dr Alison Smith

Phenotyping assays in plant pathology using detached plant parts are multi-phase experimental processes. Such assays involve growing plants in field or controlled-environment trials (Phase 1) and then subjecting a sample removed from each plant to disease assessment, usually under laboratory conditions (Phase 2). Each phase may be subject to nongenetic sources of variation. To be able to separate these sources of variation in both phases from genetic sources of variation requires a multi-phase experiment with an appropriate experimental design and statistical analysis. To achieve this, a separate randomization is required for each phase, with additional replication in Phase 2. In …

A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis

Dr Alison Smith

The statistical analysis of late-stage variety evaluation trials using a mixed model is described, with one- or two-stage approaches to the analysis. Two sets of trials, from Australia and the UK, were used to provide realistic scenarios for a simulation study to evaluate the different methods of analysis. This study showed that a one-stage approach gave the most accurate predictions of variety performance overall or within each environment, across a range of models, as measured by mean squared error of prediction or realized genetic gain. A weighted two-stage approach performed adequately for variety predictions both overall and within environments, but …

Shifts In Mid- To Late-Holocene Anion Composition In Elk Lake (Grant County, Minnesota): Comparison Of Diatom And Ostracode Inferences, Jasmine E. Saros, Sherilyn C. Fritz, Alison J. Smith

Dr Alison Smith

The fossil diatom record from Elk Lake (Grant County, Minnesota) was used to reconstruct salinity and brine type between 2640 and 4645 14C yr BP. This lake was selected for a brine-type reconstruction because a previous study using fossil-ostracode assemblages indicated a shift in anion composition during the mid-Holocene (Smith et al., 1997). Salinity was reconstructed using a transfer function developed for the Northern Great Plains (NGP) of North America; the reconstruction revealed that salinity was higher (1.5–6.2 g l−1) between ~4000 and 4645 14C yr BP and dropped to 0.35–1.2 g l−1 after 4000 14C yr BP. The anion …

Enhanced Diagnostics For The Spatial Analysis Of Field Trials, Katia Stefanova, Alison Smith, Brian Cullis

Dr Alison Smith

We report an analysis of a series of uniformity field trials using the technique proposed by Gilmour, Cullis, and Verbyla. In particular, we clarify the role of the sample variogram and present a range of enhanced graphical diagnostics to aid the spatial modeling process.We highlight the implications of the presence of extraneous variation related to commonly used agronomic practices, such as serpentine harvesting.