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Faculty of Informatics - Papers (Archive)

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Articles 1471 - 1500 of 2013

Full-Text Articles in Physical Sciences and Mathematics

Web Agents For Requirements Consistency Management, Z. Chen, Aditya K. Ghose Oct 2003

Web Agents For Requirements Consistency Management, Z. Chen, Aditya K. Ghose

Faculty of Informatics - Papers (Archive)

Inconsistency handling is an aspect of requirements engineering that has attracted considerable research attention. We explore novel ways to applying semantic Web technologies to this problem, in the context of a Web-based agent-mediated environment for distributed requirements engineering.

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A Fully Snr, Spatial And Temporal Scalable 3dspiht-Based Video Coding Algorithm For Video Streaming Over Heterogeneous Networks, H. Danyali, Alfred Mertins Oct 2003

A Fully Snr, Spatial And Temporal Scalable 3dspiht-Based Video Coding Algorithm For Video Streaming Over Heterogeneous Networks, H. Danyali, Alfred Mertins

Faculty of Informatics - Papers (Archive)

Video streaming over heterogeneous networks (e.g. the Internet) requires high degree of scalability from the video coding. To achieve all types of scalability required for a fully scalable video coding, a modification of the 3DSPIHT algorithm is presented in this paper. The proposed algorithm, called fully scalable 3DSPIHT (FS-3DSPIHT), adds spatial and temporal scalability features to the 3DSPIHT algorithm, through the introduction of resolution dependent lists and a resolution-dependent sorting pass. The important features of the original 3DSPIHT coder such as compression efficiency and full embeddedness are kept. The output bitstream of the FS-3DSPIHT encoder consists of a set of …

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Line Segment Distribution Of Sketches For Persian Signature Recognition, A. Chalechale, Alfred Mertins Oct 2003

Line Segment Distribution Of Sketches For Persian Signature Recognition, A. Chalechale, Alfred Mertins

Faculty of Informatics - Papers (Archive)

A novel fast method for line segment extraction based on chain code representation of thinned sketches (or edge maps) is presented and exploited for Persian signature recognition. The method has a parallel nature and can be employed on parallel machines. It breaks the macro chains into several micro chains after applying shifting, smoothing and differentiating. The micro chains are then approximated by straight line segments. Length and position distributions of the extracted line segments are used to make a compact feature vector for Iranian cursive signature. The feature vector is invariant under affine transforms and can be used effectively in …

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Trends In The Selection Of Automatic Identification Technology In Electronic Commerce Applications, Katina Michael Oct 2003

Trends In The Selection Of Automatic Identification Technology In Electronic Commerce Applications, Katina Michael

Faculty of Informatics - Papers (Archive)

Since the 1970s, automatic identification (auto-ID) technologies have been evolving to revolutionise the way people live and work. Previous research has not addressed auto-ID technological innovation as a field of study, despite its growing importance on consumer, business and government electronic commerce (EC) applications. This paper is specifically concerned with five auto-ID technologies, bar codes, magnetic-stripe card, smart card, biometrics and radiofrequency identification (RF/ID) tags and transponders. Using multiple embedded case studies and applying the fundamental concepts of the systems of innovation (SI) approach, the overall aim is to understand the selection environment of the auto-ID industry. The results show …

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Mpeg-21: Goals And Achievements, I. Burnett, R. Van De Walle, K. Hill, J. Bormans, F. Pereira Oct 2003

Mpeg-21: Goals And Achievements, I. Burnett, R. Van De Walle, K. Hill, J. Bormans, F. Pereira

Faculty of Informatics - Papers (Archive)

MPEG-21 is an open standards-based framework for multimedia delivery and consumption. It aims to enable the use of multimedia resources across a wide range of networks and devices. We discuss MPEG-21's parts, achievements, ongoing activities, and opportunities for new technologies.

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The Reporting Of Distribution Power Quality Surveys, V. J. Gosbell, Alex Baitch, M. H. Bollen Oct 2003

The Reporting Of Distribution Power Quality Surveys, V. J. Gosbell, Alex Baitch, M. H. Bollen

Faculty of Informatics - Papers (Archive)

Power quality surveys can contain a large amount of data for many sites and several utilities. A reporting format needs to be adopted which gives useful insights without sacrificing detail. It is recommended that a three level structure be adopted with site, network and utility component styles. The first of these is the presentation of the raw data in slightly abbreviated form while the second allows all sites in one network to be ranked according to severity of their power quality disturbances. Utility reporting allows comparison between the overall power quality performance of different utilities in benchmarking studies. Some new …

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Web Filtering Using Text Classification, R. Du, R. Safavi-Naini, Willy Susilo Sep 2003

Web Filtering Using Text Classification, R. Du, R. Safavi-Naini, Willy Susilo

Faculty of Informatics - Papers (Archive)

No abstract provided.

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Resource Aware Information Dissemination In Ad Hoc Networks, Justin Lipman, P. Boustead, Joe F. Chicharo, J. Judge Sep 2003

Resource Aware Information Dissemination In Ad Hoc Networks, Justin Lipman, P. Boustead, Joe F. Chicharo, J. Judge

Faculty of Informatics - Papers (Archive)

Information dissemination (flooding) forms an integral part of routing protocols, network management, service discovery and information collection (sensing). Given the broadcast nature of ad hoc network communications, information dissemination provides a challenging problem. This paper introduces Utility Based Flooding (UBF). UBF is a distributed optimised flooding mechanism for ad hoc networks that unlike existing optimised flooding algorithms is fully resource aware. Resource awareness is achieved by assigning a forwarding utility to neighouring nodes to determining the desirability of a neighbouring node in continuing a flood. UBF is particularly applicable to ad hoc network environments composed of heterogeneous nodes that may …

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Provisioning Content Distribution Networks Over Shared Infrastructure, T. V. Nguyen, Chuntung Chou, P. Boustead Sep 2003

Provisioning Content Distribution Networks Over Shared Infrastructure, T. V. Nguyen, Chuntung Chou, P. Boustead

Faculty of Informatics - Papers (Archive)

The current paradigm of content distribution networks (CDN) deployment requires heavy infrastructure investment since a large number of servers have to be deployed over a wide area. To overcome this difficulty, we propose a new paradigm where future CDNs are to be deployed over a leased server infrastructure. This paradigm shift changes the object placement problem in current CDNs to a combined object placement and resource provisioning problem. In this paper, we present a formulation of this problem, which is a combinatorial optimization, and prove its NP-hardness. We also present a heuristic solution to this problem based on Lagrangian relaxation …

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A Novel Dynamic Key Management Scheme For Secure Multicasting, J. Zhang, V. Varadharajan, Y. Mu Sep 2003

A Novel Dynamic Key Management Scheme For Secure Multicasting, J. Zhang, V. Varadharajan, Y. Mu

Faculty of Informatics - Papers (Archive)

We propose a new secure multicast scheme based on a novel hybrid key distribution scheme. This scheme meets the requirements described in the Internet Engineering Task Force (IETF) for multicast security architecture. It exhibits certain unique advantages in security services over existing schemes in the area of dynamic group key management. Our scheme allows efficient mechanisms for group members to join and leave a group frequently.

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Securing Mobile Ip Enabled Laptop, Rungrat Wiangsripanawan, R. Safavi-Naini, Willy Susilo Sep 2003

Securing Mobile Ip Enabled Laptop, Rungrat Wiangsripanawan, R. Safavi-Naini, Willy Susilo

Faculty of Informatics - Papers (Archive)

Mobile IP Onternet Protocol) enables access to the Internet anywhere with one IP address, hence, providing the flexibility that is required by today’s growing mobile work force. Deploying Mobile IP introduces new security h a t s that if not carefully addressed can have severe consequences for home organizations. IPSec is a commonly used protection mechanism that is employed in this context. IPSec requires a flexible key management scheme to provide cryptographic keys to communicating entities. A commonly used public key based key management system is SKIP (Simple Key-Management for Internet Protocols). In this paper we consider the scenario where …

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Tcmca: A Source-Based Distributed Topology Control Algorithm For Mission Critical Applications In Mobile Ad-Hoc Networks, G. Srivastava, P. Boustead, Joe F. Chicharo, C. Ware Sep 2003

Tcmca: A Source-Based Distributed Topology Control Algorithm For Mission Critical Applications In Mobile Ad-Hoc Networks, G. Srivastava, P. Boustead, Joe F. Chicharo, C. Ware

Faculty of Informatics - Papers (Archive)

Topology control in a wireless ad-hoc network allows better spatial reuse of the wireless channel and network resources. The existing topology control algorithms tend to optimise network power usage by keeping the topology connected but do not take the network application requirements into account. Mission critical applications which require explicit end-to-end bandwidth and delay guarantees may not find enough resources in the network with the existing network topology. We have devised a topology control algorithm for mission critical applications (TCMCA) in wireless ad-hoc networks, which adapts the network topology to improve the available resources for a set of mission critical …

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Fragile Watermark Based On Polarity Of Pixel Points, C. Kailasanathan Sep 2003

Fragile Watermark Based On Polarity Of Pixel Points, C. Kailasanathan

Faculty of Informatics - Papers (Archive)

A fragile watermarking scheme for authenticating images based on the Yeung-Mintzer scheme is proposed in this paper. This scheme does provide a better protection against all the attacks proposed for Yeung-Mintzer scheme. A polar set derived from the image blocks is used in the embedding process. The center pixel values of image blocks are perturbed by small quantities in such a way that the perceptual quality of the image is not modified. This paper also analyse the security level with respect to other attacks.

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Flexible Multichannel Blind Deconvolution, An Investigation, Ah Chung Tsoi, L. S. Ma Sep 2003

Flexible Multichannel Blind Deconvolution, An Investigation, Ah Chung Tsoi, L. S. Ma

Faculty of Informatics - Papers (Archive)

In this paper, we consider the issue of devising a flexible nonlinear function for multichannel blind deconvolution. In particular, we consider the underlying assumption of the source probability density functions. We consider two cases, when the source probability density functions are assumed to be uni-modal, and multimodal respectively. In the unimodal case, there are two approaches: Pearson function and generalized exponential function. In the multimodal case, there are three approaches: mixture of Gaussian functions, mixture of Pearson functions, and mixture of generalized exponential functions. It is demonstrated through an illustrating example that the assumption on the source probability density functions …

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Mmse Design Of Redundant Fir Precoders For Arbitrary Channel Lengths, Alfred Mertins Sep 2003

Mmse Design Of Redundant Fir Precoders For Arbitrary Channel Lengths, Alfred Mertins

Faculty of Informatics - Papers (Archive)

The joint design of transmitter and receiver for multichannel data transmission over dispersive channels is considered. The design criterion is the minimization of the mean squared error (MSE) at the receiver output under the constraint of a fixed transmit power. The focus is on the practically important case where the transmitter employs finite impulse response (FIR) filters, and the channel impulse response has arbitrary length. The proposed algorithm allows a straightforward transmitter design and generally yields near-optimal solutions for the transmit filters. Under certain conditions, the exact solutions for optimum block transmission, as known from the literature, are obtained.

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Secure Computations On Handheld Devices With The Help Of An Untrusted Server, Jianyong Huang, Willy Susilo, Jennifer Seberry Jul 2003

Secure Computations On Handheld Devices With The Help Of An Untrusted Server, Jianyong Huang, Willy Susilo, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Recently, handheld devices have become one of the most popular computing tools. Although handheld devices are able to perform anything that a PC can do, their lack of computing power makes it next to impossible to perform some heavy calculations. Hence it appears very useful to have a combination of a handheld with a PC, where the PC can perform heavy calculations to assist the handheld. However, we must be assured that the PC will not have learnt anything from the interaction. In this paper, we show two schemes which involve some server-aided computation where the server has not learnt …

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Design And Implementation Of Personal Firewalls For Handheld Devices, Jianyong Huang, Willy Susilo, Jennifer Seberry Jul 2003

Design And Implementation Of Personal Firewalls For Handheld Devices, Jianyong Huang, Willy Susilo, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Personal Digital Assistants (PDAs) have become one of the important tools in our life. Their popularity are due to their small size and mobility which enable them to be carried anywhere. Along with their popularity, handheld devices are starting to become the target for the attackers, who are mainly interested in gaining the data stored in handheld de-vices. Therefore, security of handheld devices have attracted a lot of attention in an effort to protect the sensitive information stored in handheld devices. Securing handheld de-vices is a daunting task. It requires a careful design since the devices have very limited computational …

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The Positive Model For Offshore Team Teaching, Penelope Mcfarlane, A. Fuller, K. Lam Jul 2003

The Positive Model For Offshore Team Teaching, Penelope Mcfarlane, A. Fuller, K. Lam

Faculty of Informatics - Papers (Archive)

Like many western universities, the University of Wollongong is offering degrees to an increasing number of offshore students. Our usual offshore teaching model involves intensive delivery of course material. Disadvantages of this model include the brevity of student contact with the UOW academic and delays in response to student questions and concerns regarding the subject. We discuss some results of an experiment using inexpensive and readily available Internet technologies to overcome those disadvantages.

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Improved Antenna Selection Technique To Enhance The Performance Of Wireless Communications Channels, Le Chung Tran, Tadeusz A. Wysocki, Alfred Mertins Jul 2003

Improved Antenna Selection Technique To Enhance The Performance Of Wireless Communications Channels, Le Chung Tran, Tadeusz A. Wysocki, Alfred Mertins

Faculty of Informatics - Papers (Archive)

The combination of space-time codes and a closed loop transmission diversity technique is currently receiving a lot of attention since it allows one to improve the performance of wireless communications channels. This paper proposes a simple closed loop transmission diversity technique to improve further the performance of the channels through proposing a structure of feedback information in order to reduce the time required for processing the feedback information at the transmitter. Calculations and simulations show that our technique performs especially well when it is combined with the Alamouti code.

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Scalable Speech Coding Spanning The 4 Kbps Divide, J Lukasiak, I. Burnett Jul 2003

Scalable Speech Coding Spanning The 4 Kbps Divide, J Lukasiak, I. Burnett

Faculty of Informatics - Papers (Archive)

This paper examines a scalable method for coding the LP residual. The scalable method is capable of increasing the accuracy of the reconstructed speech from a parametric representation at low rates to a more accurate waveform matched representation at higher rates. The method entails pitch length segmentation, decomposition into pulsed and noise components and modeling of the pulsed components using a fixed shape pulse model in a closed-loop, Analysis by Synthesis system. Subjective testing is presented that indicates that in addition to the AbyS modeling, the pulse parameter evolution must be constrained in synthesis. Results indicate that this proposed method …

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Low Bit Rate Wideband Wi Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak Jul 2003

Low Bit Rate Wideband Wi Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak

Faculty of Informatics - Papers (Archive)

This paper investigates waveform interpolation (WI) applied low bit rate wideband speech coding. An analysis of the evolutionary behaviour of wideband characteristic waveforms (CWs) shows that direct application of the classical WI algorithm may not be appropriate for wideband speech. We propose a modification whereby CW quantisation is performed using classical WI decomposition for the low frequency region and noise modelling for the high frequency region. Wideband WI coders incorporating this modification and operating at 4 kbps and 6 kbps are described. Subjective testing of these coders shows that WI is a promising approach to low bit rate wideband speech …

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Multi-Rate And Multi-Resolution Scalable To Lossless Audio Compression Using Pspiht, M. Raad, I. Burnett, Alfred Mertins Jul 2003

Multi-Rate And Multi-Resolution Scalable To Lossless Audio Compression Using Pspiht, M. Raad, I. Burnett, Alfred Mertins

Faculty of Informatics - Papers (Archive)

This paper presents a scalable to lossless compression scheme that allows scalability in terms of sampling rate as well as quantization resolution. The scheme presented is perceptually scalable and it also allows lossless compression. The scheme produces smooth objective scalability, in terms of SNR, until lossless compression is achieved. The scheme is built around the perceptual SPIHT algorithm, which is a modification of the SPIHT algorithm. Objective and subjective results are given that show perceptual as well as objective scalability. The subjective results given also show that the proposed scheme performs comparably with the MPEG-4 AAC coder at 16, 32 …

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An Extended Acdc Algorithm For The Blind Estimation Of Convolutive Mixing Systems, Alfred Mertins, I. Russell Jul 2003

An Extended Acdc Algorithm For The Blind Estimation Of Convolutive Mixing Systems, Alfred Mertins, I. Russell

Faculty of Informatics - Papers (Archive)

This paper presents an extension of the ACDC algorithm introduced by Yeredor for the instantaneous mixing problem to the more general convolutive mixing problem with non-white sources. Further assumptions made on the source signals are their mutual statistical independence, nonstationarity and smoothness of their power spectra. The algorithm iterates the estimation of the mixing system (AC step) and the source statistics (DC step) until convergence is achieved. The proposed algorithm operates in the frequency domain, but unlike most frequency domain algorithms, it carries out some of the operations jointly for all frequencies. This allows us to overcome frequency dependent permutation …

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The Maximal Determinant And Subdeterminants Of ±1 Matrices, Jennifer Seberry, Tianbing Xia, C. Koukouvinos, M. Mitrouli Jul 2003

The Maximal Determinant And Subdeterminants Of ±1 Matrices, Jennifer Seberry, Tianbing Xia, C. Koukouvinos, M. Mitrouli

Faculty of Informatics - Papers (Archive)

In this paper we study the maximal absolute values of determinants and subdeterminants of ±1 matrices, especially Hadamard matrices. It is conjectured that the determinants of ±1 matrices of order n can have only the values k • p, where p is specified from an appropriate procedure. This conjecture is verified for small values of n. The question of what principal minors can occur in a completely pivoted ±1 matrix is also studied. An algorithm to compute the (n — j) x (n — j), j = 1, 2, ... minors of Hadamard matrices of order n is presented, and …

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Some Results On Self-Orthogonal And Self-Dual Codes, S. Georgiou, C. Koukouvinos, Jennifer Seberry Jul 2003

Some Results On Self-Orthogonal And Self-Dual Codes, S. Georgiou, C. Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We use generator matrices G satisfying GGT = aI+bJ over Zk to obtain linear self-orthogonal and self-dual codes. We give a new family of linear self-orthogonal codes over GF(3) and Z4 and a new family of linear self-dual codes over GF(3).

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Generalized Bhaskar Rao Designs With Block Size 4 Signed Over Elementary Abelian Groups , G. Ge, M. Greig, Jennifer Seberry Jul 2003

Generalized Bhaskar Rao Designs With Block Size 4 Signed Over Elementary Abelian Groups , G. Ge, M. Greig, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

de Launey and Seberry have looked at the existence of Generalized Bhaskar Rao designs with block size 4 signed over elementary Abelian groups and shown that the necessary conditions for the existence of a (v, 4, λ; EA(g)) GBRD are sufficient for λ > g with 70 possible exceptions. This article extends that work by reducing those possible exceptions to just a (9,4,18h; EA(9h)) GBRD, where gcd(6, h) = 1, and shows that for λ = g the necessary conditions are sufficient for v > 46.

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Performance Of Mpeg-7 Low Level Audio Descriptors With Compressed Data, Jason Lukasiak, David A. Stirling, N. Harders, S. Perrow Jul 2003

Performance Of Mpeg-7 Low Level Audio Descriptors With Compressed Data, Jason Lukasiak, David A. Stirling, N. Harders, S. Perrow

Faculty of Informatics - Papers (Archive)

This paper presents a detailed analysis of lossy compression effects on a set of the MPEG-7 low-level audio descriptors. The analysis results show that lossy compression has a detrimental effect on the integrity of practical search and retrieval schemes that utilize the low level audio descriptors. Methods are then proposed to reduce the detrimental effects of compression in searching schemes. These proposed methods include multi-frame searching and machine learning derived prediction. The proposed mechanisms greatly reduce the effect of compression on the set of MPEG-7 descriptors; however, future scope is identified to develop new audio descriptors that account for compression …

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Scalable To Lossless Audio Compression Based On Perceptual Set Partitioning In Hierarchical Trees (Pspiht), M. Raad, Alfred Mertins, I. Burnett Jul 2003

Scalable To Lossless Audio Compression Based On Perceptual Set Partitioning In Hierarchical Trees (Pspiht), M. Raad, Alfred Mertins, I. Burnett

Faculty of Informatics - Papers (Archive)

This paper proposes a technique for scalable and also provides for lossless compression. It reduces smooth objective scalability, in terms of SegSNR, from lossy to lossless compression. The proposal is built around the perceptual SPIHT algorithm, which is a modification of the SPIHT algorithm and is introduced in this paper. Both objective and subjective results are reported and demonstrate that the proposed method performs comparably with the MPEG-4 AAC coder at 16, 32 and 64 kbps, yet also achieves a scalable-to-lossless architecture.

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Construction Of Highly Non-Linear Cubic Homogeneous Boolean Functions On Gf2n+L (2), Jing Wu, Tianbing Xia, Jennifer Seberry Jun 2003

Construction Of Highly Non-Linear Cubic Homogeneous Boolean Functions On Gf2n+L (2), Jing Wu, Tianbing Xia, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The work studies highly nonlinear Boolean functions in GF2n+1(2), i.e. for the dimensions where bent functions do not exist. We prove that for every n > 2 there exist homogeneous Boolean functions on GF(2)2n+1 with non-linearity greater than or equal to 22n — 2n and without linear structures.

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On Using Fast Exponentiation Algorithm In Pdas (Or: How Secure Is The Discrete Logarithm Problem Assumption In Pdas?) , Willy Susilo, Jianyong Huang, Jennifer Seberry Jun 2003

On Using Fast Exponentiation Algorithm In Pdas (Or: How Secure Is The Discrete Logarithm Problem Assumption In Pdas?) , Willy Susilo, Jianyong Huang, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Personal Digital Assistants (PDAs) are the miniature of normal size PCs, with a very limited computational power. In this paper, we investigate the security of PDAs when they are used to perform some cryptographic applications. In our context, we investigate the computation y = g' (mod p), for a prime p, which is believed to be secure in the sense of the Discrete Logarithm Problem (DLP) assumption. To be more precise, knowing only p, g and y, it is hard to derive x. We note that this computation is the most important operation in most cryptographic algorithms. However, due to …

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