Towards Automatic Assembly of Privacy-Preserved Intrusion Signatures
Intrusion signatures are used to detect and/or prevent fast-spreading worms or exploits, and usually, constructing these signatures is an automatic process without human intervention for the sake of speed. In principle, the automatic signature construction process can produce not only true-positive intrusion signatures but also false-positive ones, the latter of which poses a grave problem because they can be misused to disclose privacy information. Manual signature checking (for a whitelist) can solve the problem, but it slows down the reaction time for an attack dramatically. In this paper, we propose a mechanism to generate signatures automatically while preserving the privacy information. Essentially, we transform the original feature values within an audit trail instance into feature ranges, and then use these feature ranges to construct a privacy-preserved intrusion signature. Our current focus is on the methods constructing feature ranges, and for this purpose, several methods are proposed to discover feature ranges. The experimental results are quite encouraging: the transformation from values to ranges leads not only to the preservation of privacy but also to the enhancement of the detection performance.

title: Observations on Non-repudiation
abstract: This paper discusses non-repudiation services regarding the transfer of a message and classifies the roles of trusted third parties involved in non-repudiation services. We examine the selective receipt problem and the generation of time evidence, analyse the current state of the ISO/IEC 13888 drafts on non-repudiation mechanisms, and present a fair non-repudiation protocol including time evidence to promote the development of these drafts.

title: Efficient Signature Validation Based on a New PKI
abstract: Digital signatures usually serve as irrefutable cryptographic evidence to support dispute resolution in electronic transactions. Trusted time-stamping and certificate revocation services, although very costly in practice, must be available to prevent big loss due to compromising of the signing key. In this paper, we employ a revocation-free public-key framework to improve the efficiency in maintaining the validity of digital signatures as non-repudiation evidence. The new PKI allows an end user to control the validity of his own public-key certificate and enables certificate verification without retrieving the revocation information from the CA. Based on this new PKI, we could validate generic digital signatures using a TSA only. Moreover, we could validate forward-secure digital signatures without the TTP’s involvement.

title: Securing digital signatures for non-repudiation
abstract: Dispute of transactions is a common problem that could jeopardise business. Hence non-repudiation services are essential in business transactions which provide evidence to enable dispute resolution. To be eligible as non-repudiation evidence, the digital signature on an electronic document should remain valid until its expiry date which is specified by some non-repudiation policy. The conventional approaches are either inefficient or insecure to achieve non-repudiation in electronic commerce. This article presents a practical scheme to secure digital signatures as non-repudiation evidence with an adjustable degree of risk.

title: Non-Repudiation in Electronic Commerce
abstract: Electronic Commerce and Security. Repudiation and Dispute Resolution. Non-Repudiation and Network Security. Non-Repudiation in Message Handling Systems. Non-Repudiation in Electronic Payment Systems. Book Outline. Fundamentals of Non-Repudiation - Goals of Non-Repudiation. Non-Repudiation Services. Non-Repudiation Evidence. Roles of Trusted Third Parties. Phases of Non-Repudiation. Non-Repudiation Policy. Requirements for Non-Repudiation. Securing Digital Signatures for Non-Repudiation - Security Requirements on Digital Signatures. Time Stamps in Digital Signatures. Securing TTP's Digital Signatures. Time-Stamping Approach.  One-Way Sequential Link Approach.   Achieving Fair Non-Repudiation - Factors against Fair Non-Repudiation. Approaches for Fair Non-Repudiation.  Using Light-Weighted On-Line TTP.  Using Off-Line TTP without Timely Termination.  Using Off-Line TTP with Timely Termination.  Using In-Line TTP for Timely Delivery.  Related Work on Fair Non-Repudiation - Protocols Using In-Line TTP. Protocols Using On-Line TTP. Protocols Using Off-Line TTP. Protocols with Probablistic Fairness.  ISO's Non-Repudiation Mechanisms - Overview of ISO/IEC 13888. Mechanisms Using Symmetric Techniques. Mechanisms Using Asymmetric Techniques. Time-Stamping Evidence.  Case Studies - Non-Repudiation in Electronic Payment. Undeniable Billing in Mobile Communication.  Towards Formal Verification of Non-Repudiation - The SVO Logic. Formalization of Non-Repudiation. Verification of a Non-Repudiation Protocol.

title: An intensive survey of fair non-repudiation protocols
abstract: With the phenomenal growth of the Internet and open networks in general, security services, such as non-repudiation, become crucial to many applications. Non-repudiation services must ensure that when Alice sends some information to Bob over a network, neither Alice nor Bob can deny having participated in a part or the whole of this communication. Therefore a fair non-repudiation protocol has to generate non-repudiation of origin evidences intended to Bob, and non-repudiation of receipt evidences destined to Alice. In this paper, we clearly define the properties a fair non-repudiation protocol must respect, and give a survey of the most important non-repudiation protocols without and with trusted third party (TTP). For the later ones we discuss the evolution of the TTP's involvement and, between others, describe the most recent protocol using a transparent TTP. We also discuss some ad-hoc problems related to the management of non-repudiation evidences.

title: Algorithm Selectors for Providing Location Estimation Services within a Cellular Radio Network
abstract: Mobile location estimation is becoming an important value-added service for mobile phone operators. Many mobile location estimation algorithms based on the cellular radio networks have been proposed but there exists no general solution since each algorithm has its own advantage depending on specific terrain and environmental factors. In this paper, we propose and investigate three algorithm selectors, one with a LDA classifier and the other two with Bayes classifiers using either a Naive Bayes probabilistic model or a Bayes probabilistic model, to select the best mobile location estimation algorithms from our previous work in order to combine their merits, and provide a more accurate estimation for location services. We have tested these three algorithm selectors with real data taken in Hong Kong. Experiment results have shown that they are all useful in particular, and the one with a Bayes probabilistic model outperforms all other existing location algorithms among different kinds of terrains in terms of average errors

title: A selector method for providing mobile location estimation services within a radio cellular network
abstract: Mobile location estimation or mobile positioning is becoming an important service for a mobile phone network. It is well-known that GPS can provide accurate location estimation, but it is also a known fact that GPS does not perform well in urban areas like downtown New York and cities like Hong Kong. Then many mobile location estimation approaches based on radio cellular networks have been proposed to compensate the problem of the lost of GPS signals in providing location services to mobile users in metropolitan areas. In this paper, we present a selector method with the linear discriminant analysis (LDA) among different kinds of mobile location estimation technologies we had proposed in previous work in order to combine their merits, then provide a more accurate estimation for location services. We build up a three-level binary tree to classify these four algorithms. These three levels are named as Stat-Geo level, CG-nonCG level and CT-EPM level. And these success ratios of these three levels are 85.22%, 88.45% and 88.89% respectively. We have tested our selector method with real data taken in Hong Kong and it is proven that it outperforms other existing location estimation algorithms among different kinds of terrains.

title: Automatic detection of premature ventricular contraction using quantum neural networks
abstract: Premature ventricular contractions (PVCs) are ectopic heart beats originating from ventricular area. It is a common form of heart arrhythmia. Electrocardiogram (ECG) recordings have been widely used to assist cardiologists to diagnose the problem. In this paper, we study the automatic detection of PVC using a fuzzy artificial neural network named Quantum Neural Network (QNN). With the quantum neurons in the network, trained QNN can model the levels of uncertainty arising from complex classification problems. This fuzzy feature is expected to enhance the reliability of the algorithm, which is critical for the applications in the biomedical domain. Experiments were conducted on ECG records in the MIT-BIH Arrhythmia Database. Results showed consistently higher or same reliability of QNN on all the available records compared to the backpropagation network. QNN, however, has a relatively higher resource requirement for training.

title: Image Rectification for Stereoscopic Visualization Without 3D Glasses
abstract: There exist various methods for stereoscopic viewing of images, most requiring that a viewer wears some special glasses. Recent technology developments have resulted in displays that enable 3D viewing without glasses. In this paper, we present results from our proposed approach to automatic rectification of two images of the same scene captured by cameras at general positions, so that the results can be viewed on a 3D display. Both simulated and real data experiments are presented.

title: Unconstrained numeral pair recognition using enhanced error correcting output coding: a holistic approach
abstract: This paper describes a new approach to recognize touching numeral strings. Currently most methods for numeral string recognition require segmenting the string image into separate numerals. As a result, the recognition system heavily depends on the reliability of the segmentation module. This study explores the holistic strategy directly on the string images without segmentation. It builds the novel classifier by combining binary classifiers based on data-driven error correcting output coding (DECOC). The dimensions of input images are reduced using principal components analysis. Support vector machines are used as base learners. Experiments on NIST SD19 touching numeral pairs confirm that DECOC can achieve favorable performance compared with other multi-class holistic classifiers. The method provides the flexibility of controlling the computational complexity versus accuracy. We also discuss an implementation suitable for distributing computing by decomposing the ensemble into subtasks.