14361062
An electronic payment scheme allowing special rates for anonymous regular customers
Anonymous electronic payment systems are regarded as essential for the protection of the privacy of consumers participating in electronic transactions. In this paper, we present an electronic payment scheme which allows regular customers not only to get special rates from the merchant but also to be kept anonymous to the merchant.
1762691
Non-Repudiation in Electronic Commerce
Introduction - 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. Auditing Approach. One-Way Sequential Link Approach. Temporary Certificate Approach. Comparison. Summary. Achieving Fair Non-Repudiation - Factors against Fair Non-Repudiation. Approaches for Fair Non-Repudiation. Protocol NR1: Using Light-Weighted On-Line TTP. Protocol NR2: Using Off-Line TTP without Timely Termination. Protocol NR3: Using Off-Line TTP with Timely Termination. Protocol NR4: Using In-Line TTP for Timely Delivery. Summary. 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. Summary. ISO's Non-Repudiation Mechanisms - Overview of ISO/IEC 13888. Mechanisms Using Symmetric Techniques. Mechanisms Using Asymmetric Techniques. Time-Stamping Evidence. Summary. Case Studies - Non-Repudiation in Electronic Payment. Undeniable Billing in Mobile Communication. Summary. Conclusion. Towards Formal Verification of Non-Repudiation - The SVO Logic. Formalization of Non-Repudiation. Verification of a Non-Repudiation Protocol. Summary.
1909548
An intensive survey of fair non-repudiation protocols
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.
26863874
Efficient Signature Validation Based on a New PKI
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.
2500764
Securing digital signatures for non-repudiation
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.
40659634
Observations on Non-repudiation
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.
17429132
Rule-base technique for component adaptation to support QoS-based reconfiguration
Many critical application systems require reconfigurability in order to adapt under changing environment. To achieve system reconfigurability, it is possible to use adaptation mechanisms that are external to components or to use parameterized components. This paper focuses on making components reconfigurable in terms of QoS tradeoffs. We propose a new component parameterization technique which can transform individual components to reconfigurable ones such that they can support various QoS tradeoffs to achieve overall system QoS requirements. The parameterized components can be used to develop both statically and dynamically reconfigurable systems. The proposed technique is rule based, which provides flexibility and extensibility to enhance and improve the technique. A tool set has been developed based on the proposed technique to achieve semi-automated component parameterization.
24637239
A rule-based component customization technique for QoS properties
Component customization technique is an important part of component-based development (CBD) process. It allows the component to be effectively adapted and reused in diverse applications. However, existing component customization techniques focus on customizing the functionality of a component. Embedded systems generally have strict quality of service (QoS) requirements such as timeliness, memory limitations, output precisions, etc. Currently, customization for the satisfaction of QoS requirements has not been widely addressed. To address the problem, we propose the concept of configurable parameter. A configurable parameter is a constant or a variable defined in a component which, when adjusted, can provide QoS trade-offs. A QoS properties reconfigurable (QoS-R) component is a software component which can be reconfigured either statically or dynamically to provide desired QoS tradeoffs. In this paper, we present our current results in developing a new, systematic code parameterization technique which focuses on identifying configurable parameters in components and converting them into QoSR components.
17064783
Implementing database operations using SIMD instructions
Modern CPUs have instructions that allow basic operations to be performed on several data elements in parallel. These instructions are called SIMD instructions, since they apply a single instruction to multiple data elements. SIMD technology was initially built into commodity processors in order to accelerate the performance of multimedia applications. SIMD instructions provide new opportunities for database engine design and implementation. We study various kinds of operations in a database context, and show how the inner loop of the operations can be accelerated using SIMD instructions. The use of SIMD instructions has two immediate performance benefits: It allows a degree of parallelism, so that many operands can be processed at once. It also often leads to the elimination of conditional branch instructions, reducing branch mispredictions.We consider the most important database operations, including sequential scans, aggregation, index operations, and joins. We present techniques for implementing these using SIMD instructions. We show that there are significant benefits in redesigning traditional query processing algorithms so that they can make better use of SIMD technology. Our study shows that using a SIMD parallelism of four, the CPU time for the new algorithms is from 10% to more than four times less than for the traditional algorithms. Superlinear speedups are obtained as a result of the elimination of branch misprediction effects.
26054597
Image Rectification for Stereoscopic Visualization Without 3D Glasses
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.
626554
Buffering databse operations for enhanced instruction cache performance
As more and more query processing work can be done in main memory access is becoming a significant cost component of database operations. Recent database research has shown that most of the memory stalls are due to second-level cache data misses and first-level instruction cache misses. While a lot of research has focused on reducing the data cache misses, relatively little research has been done on improving the instruction cache performance of database systems.We first answer the question "Why does a database system incur so many instruction cache misses?" We demonstrate that current demand-pull pipelined query execution engines suffer from significant instruction cache thrashing between different operators. We propose techniques to buffer database operations during query execution to avoid instruction cache thrashing. We implement a new light-weight "buffer" operator and study various factors which may affect the cache performance. We also introduce a plan refinement algorithm that considers the query plan and decides whether it is beneficial to add additional "buffer" operators and where to put them. The benefit is mainly from better instruction locality and better hardware branch prediction. Our techniques can be easily integrated into current database systems without significant changes. Our experiments in a memory-resident PostgreSQL database system show that buffering techniques can reduce the number of instruction cache misses by up to 80% and improve query performance by up to 15%.