15503890
Provide privacy for mobile P2P systems
Nowadays privacy and anonymity have become an increasing requirement in wireless networks. However, current mobile peer-to-peer architectures have not taken into account anonymity, especially the mutual anonymity between two nodes. In this paper, we propose a mutual anonymity protocol, called secret-sharing-based mutual anonymity protocol (SMA), for mobile P2P networks. Our simulation results show that SMA achieves mutual anonymity in mobile P2P networks with a low cryptography processing overhead.
17887061
Popularity Biased Hybrid Search in P2P Systems
Hybrid search, which combines the flooding and DHT techniques, has been employed for efficient content-locating in peer-to-peer (P2P) systems. Choosing a flooding or a DHT subjects to the population of desired data. However, existing studies summarizes the popularity only based on local information, or does not take into account the dynamic factor of P2P systems. Thus, the users suffer from long search latency when performing hybrid search due to inaccurate estimations of the resource popularity. In this paper, we propose a popularity biased hybrid search method in systems. Our model allows the P2P systems dynamically detect the content popularity, and accurately make a decision of search methods. In this way, our work effectively reduces the query traffic cost and response time. The result our trace-driven simulations report shows that our model outperforms existing approaches in search efficiency
15978422
TruGrid: a self-sustaining trustworthy grid
In typical distributed environments, there are two parties: consumers and providers. Consumers have computational jobs while may lack of computational resources. Providers have relatively underutilized resources. With the rapid advancement in high-speed networks, how to enable the effective and secure interaction between consumers and providers has become increasingly important. Because of the distributed ownership of resources, however, it is a very challenging problem. We propose the TruGrid, a self-sustaining trustworthy grid, to solve it. The TruGrid is a novel loosely connected grid system, which guarantees the incentive of every participant and therefore it is a self-sustaining system. We also identify two security challenges arising in the TruGrid, i.e., free-rider and boaster. The proposed trustworthiness management and the penalty model successfully overcome the challenges. Simulation results demonstrate that the TruGrid is a promising actuator to enable the interaction between autonomous consumers and providers.
6112726
Pseudo Trust: Zero-Knowledge Based Authentication in Anonymous Peer-to-Peer Protocols
Most of the current trust models in peer-to-peer (P2P) systems are identity based, which means that in order for one peer to trust another, it needs to know the other peer's identity. Hence, there exists an inherent tradeoff between trust and anonymity. To the best of our knowledge, there is currently no P2P protocol that provides complete mutual anonymity as well as authentication and trust management. We propose a zero-knowledge authentication scheme called pseudo trust (PT), where each peer, instead of using its real identity, generates an unforgeable and verifiable pseudonym using a one-way hash function. A novel authentication scheme based on zero-knowledge proof is designed so peers can be authenticated without leaking any sensitive information. With the help of PT, most existing identity-based trust management schemes become applicable in mutual anonymous P2P systems. We analyze the levels of security and anonymity in PT, and evaluate its performance using trace-driven simulations and a prototype implementation. The strengths of pseudo trust include the lack of need for a centralized trusted party or CA, high scalability and security, low traffic and cryptography processing overheads, and man-in-middle attack resistance. We aim for the pseudo trust design to be included in the P2P trust and anonymity context.
27160507
A Random Walk Based Anonymous Peer-to-Peer Protocol Design
Anonymity has been one of the most challenging issues in Ad Hoc environment such as P2P systems. In this paper, we propose an anonymous protocol called Random Walk based Anonymous Protocol (RWAP), in decentralized P2P systems. We evaluate RWAP by comprehensive trace driven simulations. Results show that RWAP significantly reduces traffic cost and encryption overhead compared with existing approaches.
40646697
HAND: An Overlay Optimization Algorithm in Peer-to-Peer Systems
Recently, peer-to-peer (P2P) model becomes popular due to its outstanding resource sharing ability in large-scale distributed systems. However, the most popular P2P system – unstructured P2P system, suffers greatly from the mismatching between the logical overlay and physical topology. This mismatching problem causes a large volume of redundant traffic, which makes peer-to-peer system far from scalable and degrades their search efficiency dramatically. In this paper we address the mismatching problem in an unstructured P2P architecture by developing a distributed overlay optimizing algorithm – HAND (Hops Adaptive Neighbor Discovery). Through comprehensive simulations, we show that HAND significantly outperforms previous approaches, especially in large-scale P2P systems.
16419602
Software Documents: Concepts and Tools
In this paper, we review software development as a document-based process, with the capture of a full but ideal development history as the assumed purpose of the documents concerned. We identify generic requirements for perusal, editing and veriication of such documents, and illustrate how these requirements could be met in a software development environment based on current interaction technology. Finally, we propose a generic environment architecture for implementation of the facilities concerned, and outline how our own research work has addressed some of the requirements of this architecture.
14721307
Specifying Interaction Constraints of Software Components for Better Understandability and Interoperability
A vital issue in the correct use of commercial-off-the-shelf (COTS) components is the proper understanding of their functionality, quality attributes and ways of operation. Traditionally, COTS component vendors provide some of this information in accompanying documentation. However, the documentation is often informal and likely contains ambiguous and inconsistent statements. Even equipped with interface descriptions clearly defining the basic aspects of component use, such as operation signatures and operating platforms, this documentation does not provide a mathematically sound means for addressing the behavioural interoperability issues in component-based system design. In this paper, we propose a formal but user-friendly component specification approach which augments commercial IDLs with the capability of capturing component interoperability requirements. This approach uses unambiguous temporal operators to define sequencing and concurrency constraints between component operation invocations. Accordingly, it enables precise specifications of how a component provides its services and the correct way in which its services should be used.
2940771
Graph indexing: a frequent structure-based approach
Graph has become increasingly important in modelling complicated structures and schemaless data such as proteins, chemical compounds, and XML documents. Given a graph query, it is desirable to retrieve graphs quickly from a large database via graph-based indices. In this paper, we investigate the issues of indexing graphs and propose a novel solution by applying a graph mining technique. Different from the existing path-based methods, our approach, called gIndex, makes use of frequent substructure as the basic indexing feature. Frequent substructures are ideal candidates since they explore the intrinsic characteristics of the data and are relatively stable to database updates. To reduce the size of index structure, two techniques, size-increasing support constraint and discriminative fragments, are introduced. Our performance study shows that gIndex has 10 times smaller index size, but achieves 3--10 times better performance in comparison with a typical path-based method, GraphGrep. The gIndex approach not only provides and elegant solution to the graph indexing problem, but also demonstrates how database indexing and query processing can benefit form data mining, especially frequent pattern mining. Furthermore, the concepts developed here can be applied to indexing sequences, trees, and other complicated structures as well.
5983751
Fusion of color and infrared video for moving human detection
We approach the task of human silhouette extraction from color and thermal image sequences using automatic image registration. Image registration between color and thermal images is a challenging problem due to the difficulties associated with finding correspondence. However, the moving people in a static scene provide cues to address this problem. In this paper, we propose a hierarchical scheme to automatically find the correspondence between the preliminary human silhouettes extracted from synchronous color and thermal image sequences for image registration. Next, we discuss strategies for probabilistically combining cues from registered color and thermal images for improved human silhouette detection. It is shown that the proposed approach achieves good results for image registration and human silhouette extraction. Experimental results also show a comparison of various sensor fusion strategies and demonstrate the improvement in performance over non-fused cases for human silhouette extraction.
1199528
Specifying Dynamic Security Properties of Web Service Based Systems
The security characteristics of web service based systems depend on those of the individual web services (WS) involved and the way in which they are related to each other. In principle, the security characteristics of WS or systems can be expressed in security properties that are published and available to external parties. Only by knowing the security properties of the individual WS another WS can invoke it (if it satisfies certain security requirements and capabilities) and the overall system?s security properties can be analysed and deduced. In our earlier work, we have developed the security characterisation language, SCL, to specify the static security properties of software components and systems. In this paper, we use SCL for describing security properties of WS and further enhance this language with the capability of specifying the dynamic security characteristics. The extended version of SCL (E-SCL) incorporates such features as time, time intervals, time sequence, probability, runtime conditions, and alternative security properties. Furthermore, we have developed the WS security ontology and applied it together with E-SCL to publish the dynamic security properties of WS using OWL-S and analyse them dynamically. Our approach is illustrated with an example email system.