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Walid Bagga Stefano Crosta Pietro Michiardi Refik Molva 《Electronic Notes in Theoretical Computer Science》2007,171(1):107
A policy-based encryption scheme allows to encrypt a message according to a credential-based policy formalized as monotone Boolean expression written in standard normal form. The encryption is so that only the users having access to a qualified set of credentials for the policy are able to decrypt the message. In this paper, we first revisit the formal definition of policy-based encryption and describe a policy-based encryption scheme from bilinear pairings. Our scheme improves the one proposed in [W. Bagga and R. Molva. Policy-based cryptography and applications. In Proceedings of Financial Cryptography and Data Security (FC'05), volume 3570 of LNCS, pages 72–87. Springer-Verlag, 2005] in terms of ciphertext size, while at the same time preserving the computational efficiency. Then, we describe an application of policy-based encryption in the context of ad-hoc networks. More precisely, we show how the policy-based encryption primitive can be used to achieve a privacy-enhanced secure establishment of ad-hoc communities. 相似文献
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In this article we investigate the impacts of interspacing and source polling policies on the cell‐loss rates in transmission
of variable bit rate video sources over Asynchronous Transfer Mode networks. We present a mathematical model that finds the
approximate optimal starting times of the video sources that minimize the congestion at the multiplexer. Combined with the
approximate optimal source starting times, we propose a source ordering and polling policy for reducing the cell‐loss rates.
The proposed policy is tested against alternative policies using simulation of pre‐recorded video data.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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The response of a Goto pair, based on small-size Josephson junctions, to voltage jumps has been studied within the framework
of a resistive model. An analytical formula for the time of establishment of the transfer characteristic is obtained and the
corresponding estimates are calculated. 相似文献
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The monitoring of the quality of service in digital television networks needs instruments to assess automatically the perceived quality of audio and video components of an MPEG2 signal. In order to improve the knowledge of the impact of the impairments on the final service, and to validate the algorithms that will be implemented in the quality evaluation instruments, a general simulation chain has been designed and developed. This paper presents the simulations performed as well as the analysis and the synthesis of the obtained results 相似文献
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Alessandro Sorniotti Refik Molva Laurent Gomez Christophe Trefois Annett Laube Piervito Scaglioso 《International Journal of Wireless Information Networks》2009,16(3):165-174
Although very developed in many sectors (databases, filesystems), access control schemes are still somewhat elusive when it
comes to wireless sensor networks. However, it is clear that many WSN systems—such as healthcare and automotive ones—need
a controlled access to data that sensor nodes produce, given its high sensitivity. Enforcing access control in wireless sensor
networks is a particularly difficult task due to the limited computational capacity of wireless sensor nodes. In this paper
we present a full-fledged access control scheme for wireless sensor data. We enforce access control through data encryption,
thus embedding access control in sensor data units. We also propose a lightweight key generation mechanism, based on cryptographic
hash functions, that allows for hierarchical key derivation. The suggested protocol only relies on simple operations, does
not require interactions between nodes and data consumers and has minimal storage requirements.
Alessandro Sorniotti has a double MSc degree from Politecnico di Torino (Turin, Italy) in Computer Science and from EURECOM in Networking. He also obtained a Research Master diploma (DOA) in Networking and Distributed Systems from Université de Nice-Sophia Antipolis (UNSA, Nice, France). Alessandro has won a scholarship (bourse CIFRE) and he is a PhD candidate at ENST, working as a Research Associate at SAP Labs France. His current research topic is the study of protocols for Secret Exchange, Secret Matching and Secret Handshake. Refik Molva is a full professor and the head of the Computer Communications Department at Institute Eurécom in Sophia Antipolis, France. His current research interests are the design and evaluation of protocols for security and privacy in self-organizing systems. He previously worked on several research projects on multicast and mobile network security, anonymity and intrusion detection. Beside security, he worked on distributed multimedia applications over high speed networks and on network interconnection. Prior to joining Eurécom, he worked in the Zurich Research Laboratory of IBM where he was one of the key designers of the KryptoKnight security system. He also worked as a consultant in security for the IBM Consulting Group. He has a PhD in Computer Science from the Paul Sabatier University in Toulouse (1986) and a BSc in Computer Science (1981) from Joseph Fourier University, Grenoble, France. Laurent Gomez is a senior researcher at SAP Research France since 2001. He is currently involved in WASP and ATLAS projects. His research activities are focused on security and context-aware systems. Prior to joining SAP Research, Laurent Gomez worked as engineer at research projects for Ericsson. He has a strong background in security of mobile applications, with a focus on context-aware systems. Laurent holds a Engineer Degree in Computing Systems from ESSI (Ecole Superieure en Sciences Informatique), Nice France. Christophe Trefois received his BSc degree in Communication Systems from the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland in 2006. In 2008, he obtained his MSc degree in Communication Systems from EPFL. From March to August 2008, he worked as a Research Assistant at SAP Labs France in Sophia Antipolis. Christophe is currently working as an IT Consultant at Ernst & Young Luxembourg and is a member of the ISACA Lux Chapter. Annett Laube joined SAP Research Security & Trust program in 2006. She is a senior researcher currently leading in the WASP project. Prior to joining SAP, she worked at IBM Scientific Center in Heidelberg in the areas of machine translation of natural languages and text mining. Later she worked as an IBM consultant for e-business and data warehouse. In parallel she wrote her PhD thesis about the translation of dependency structures in the transfer process from one natural language to another. She started to work for SAP in 2001 at SAP Labs Montreal/Quebec and worked as a software developer for Supply Chain Event Management. Piervito Scaglioso received his MSc degree from Politecnico di Torino in 2006. He is currently enrolled as PhD student in the Department of Computer Science at the Politecnico di Torino. His research interests include: Policy-based system and their application to manage access control, access control for wireless sensor network and hierarchical key management scheme. 相似文献
Piervito ScagliosoEmail: |
Alessandro Sorniotti has a double MSc degree from Politecnico di Torino (Turin, Italy) in Computer Science and from EURECOM in Networking. He also obtained a Research Master diploma (DOA) in Networking and Distributed Systems from Université de Nice-Sophia Antipolis (UNSA, Nice, France). Alessandro has won a scholarship (bourse CIFRE) and he is a PhD candidate at ENST, working as a Research Associate at SAP Labs France. His current research topic is the study of protocols for Secret Exchange, Secret Matching and Secret Handshake. Refik Molva is a full professor and the head of the Computer Communications Department at Institute Eurécom in Sophia Antipolis, France. His current research interests are the design and evaluation of protocols for security and privacy in self-organizing systems. He previously worked on several research projects on multicast and mobile network security, anonymity and intrusion detection. Beside security, he worked on distributed multimedia applications over high speed networks and on network interconnection. Prior to joining Eurécom, he worked in the Zurich Research Laboratory of IBM where he was one of the key designers of the KryptoKnight security system. He also worked as a consultant in security for the IBM Consulting Group. He has a PhD in Computer Science from the Paul Sabatier University in Toulouse (1986) and a BSc in Computer Science (1981) from Joseph Fourier University, Grenoble, France. Laurent Gomez is a senior researcher at SAP Research France since 2001. He is currently involved in WASP and ATLAS projects. His research activities are focused on security and context-aware systems. Prior to joining SAP Research, Laurent Gomez worked as engineer at research projects for Ericsson. He has a strong background in security of mobile applications, with a focus on context-aware systems. Laurent holds a Engineer Degree in Computing Systems from ESSI (Ecole Superieure en Sciences Informatique), Nice France. Christophe Trefois received his BSc degree in Communication Systems from the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland in 2006. In 2008, he obtained his MSc degree in Communication Systems from EPFL. From March to August 2008, he worked as a Research Assistant at SAP Labs France in Sophia Antipolis. Christophe is currently working as an IT Consultant at Ernst & Young Luxembourg and is a member of the ISACA Lux Chapter. Annett Laube joined SAP Research Security & Trust program in 2006. She is a senior researcher currently leading in the WASP project. Prior to joining SAP, she worked at IBM Scientific Center in Heidelberg in the areas of machine translation of natural languages and text mining. Later she worked as an IBM consultant for e-business and data warehouse. In parallel she wrote her PhD thesis about the translation of dependency structures in the transfer process from one natural language to another. She started to work for SAP in 2001 at SAP Labs Montreal/Quebec and worked as a software developer for Supply Chain Event Management. Piervito Scaglioso received his MSc degree from Politecnico di Torino in 2006. He is currently enrolled as PhD student in the Department of Computer Science at the Politecnico di Torino. His research interests include: Policy-based system and their application to manage access control, access control for wireless sensor network and hierarchical key management scheme. 相似文献
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Unsupervised clustering and clustering validity are used as essential instruments of data analytics. Despite clustering being realized under uncertainty, validity indices do not deliver any quantitative evaluation of the uncertainties in the suggested partitionings. Also, validity measures may be biased towards the underlying clustering method. Moreover, neglecting a confidence requirement may result in over-partitioning. In the absence of an error estimate or a confidence parameter, probable clustering errors are forwarded to the later stages of the system. Whereas, having an uncertainty margin of the projected labeling can be very fruitful for many applications such as machine learning. Herein, the validity issue was approached through estimation of the uncertainty and a novel low complexity index proposed for fuzzy clustering. It involves only uni-dimensional membership weights, regardless of the data dimension, stipulates no specific distribution, and is independent of the underlying similarity measure. Inclusive tests and comparisons returned that it can reliably estimate the optimum number of partitions under different data distributions, besides behaving more robust to over partitioning. Also, in the comparative correlation analysis between true clustering error rates and some known internal validity indices, the suggested index exhibited the highest strong correlations. This relationship has been also proven stable through additional statistical acceptance tests. Thus the provided relative uncertainty measure can be used as a probable error estimate in the clustering as well. Besides, it is the only method known that can exclusively identify data points in dubiety and is adjustable according to the required confidence level. 相似文献
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In this article, we consider the development and analysis of both attribute- and variable-data reliability growth models from a Bayesian perspective. We begin with an overview of a Bayesian attribute-data reliability growth model and illustrate how this model can be extended to cover the variable-data growth models as well. Bayesian analysis of these models requires inference over ordered regions, and even though closed-form results for posterior quantities can be obtained in the attribute-data case, variable-data models prove difficult. In general, when the number of test stages gets large, computations become burdensome and, more importantly, the results may become inaccurate due to computational difficulties. We illustrate how the difficulties in the posterior and predictive analyses can be overcome using Markov-chain Monte Carlo methods. We illustrate the implementation of the proposed models by using examples from both attribute and variable reliability growth data. 相似文献
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Two of the main parameters of real-time computer systems are reliability and performance. Researchers are always looking for solutions to increase the values of these parameters, which is the goal of this study. To this end, we propose an architecture for a dual-computer system that operates in real-time with fault tolerance implemented purely by hardware. The hardware, as designed and implemented, performs the following key services: 1) determination of the fault type (temporary or permanent) and 2) localization of the faulty computer without using self-testing techniques or diagnostic routines. Our design has several benefits: 1) the designed hardware shortens the recovery point time period; 2) the proposed nontrivial sequence of fault-tolerant services reduces (to two) the number of logical segments that must be re-run to recover computational processes; and 3) the determination of the fault type allows for the elimination of only computers with permanent faults. These contributions yield improvements in both the performance and reliability of the system. 相似文献