Current Issue : October - December Volume : 2013 Issue Number : 4 Articles : 5 Articles
In vehicular ad hoc networks (VANETs), some distinct characteristics, such as high node mobility, introduce new\r\nnon-trivial challenges to quality-of-service (QoS) provisioning. Although some excellent works have been done on\r\nQoS issues in VANETs, security issues are largely ignored in these works. However, it is know that security always\r\ncomes at a price in terms of QoS performance degradation. In this article, we consider security and QoS issues jointly\r\nfor VANETs with cooperative communications. We take an integrated approach of optimizing both security and QoS\r\nparameters, and study the tradeoffs between them in VANETs. Specifically, we use recent advances in cooperative\r\ncommunication to enhance the QoS performance of VANETs. In addition, we present a prevention-based security\r\ntechnique that provides both hop-by-hop and end-to-end authentication and integrity protection. We derive the\r\nclosed-form effective secure throughput considering both security and QoS provisioning in VANETs with cooperative\r\ncommunications. The system is formulated as a partially observable Markov decision process. Simulation results are\r\npresented to show that security schemes have significant impacts on the throughput QoS of VANETs, and our\r\nproposed scheme can substantially improve the effective secure throughput of VANETs with cooperative...
This article details the conception, design, development and analysis of invisible, blind and robust color image\r\nwatermarking algorithms based on the wavelet transform. Using error correcting codes, the watermarking algorithms\r\nare designed to be robust against intentional or unintentional attacks such as JPEG compression, additive white\r\nGaussian noise, low pass filter and color attacks (hue, saturation and brightness modifications). Considering the\r\nwatermarking channel characterized by these attacks, repetition, Hamming, Bose Chaudhuri Hocquenghem and\r\nReed-Solomon codes are used in order to improve the robustness using different modes and appropriate decoding\r\nalgorithms. The article compares the efficiency of different type of codes against different type of attacks. To the best\r\nof our knowledge this is the first time that the effect of error-correcting codes against different attacks are detailed in a\r\nwatermarking context in such a precise way: describing and comparing the effect of different classes of codes against\r\ndifferent type of attacks. This article clearly shows that list decoding of Reed-Solomon codes using the algorithm of\r\nSudan exhibits good performance against hue and saturation attacks. The use of error correcting codes in a\r\nconcatenation mode allows the non-binary block codes to show good performance against JPEG compression,\r\nnoise and brightness attacks....
In this paper, a joint subcarrier and power allocation algorithm is proposed to improve the physical layer security in\r\ncooperative orthogonal frequency division multiple access (OFDMA) networks, where several source-destination pairs\r\nand one untrusted relay are involved. The relay is friendly and intends to help these pairs to enhance their\r\ncommunications. However, it may be overheard by a malicious eavesdropper at the same time. To optimize the joint\r\nsubcarrier and power allocation with low complexity, we divide the optimization problem into two simpler\r\nsubproblems. Firstly, the subcarriers are assigned to the source-destination pairs by employing the dual approach\r\nunder the assumption that the relay power is equally allocated to all the subcarriers. Then, the relay power is allocated\r\nto the subcarriers based on the alternative ascending clock auction mechanism. In addition, we prove that the two\r\nsubproblems can converge after a finite number of iterations. We also find that the proposed auction is cheat-proof\r\nand, thus, can avoid the cheating behaviors in the auction process. Numerical results demonstrate that our proposed\r\nalgorithm can effectively improve the system sum secrecy rate, and the convergence performance is also desirable....
This paper introduces a formal metamodel for the\r\nspecification of security policies for workflows in online service\r\nsystems designed to be suitable for the modeling and analysis of\r\ncomplex business-related rules as well as traditional access\r\ncontrol. A translation of the model into a colored Petri net is\r\nshown and an example of policy for an online banking system is\r\ndescribed. By writing predicates for querying the resulting statespace\r\nof the Petri net, a connection between the formalized model\r\nand a higher-level description of the security policy can be made,\r\nindicating the feasibility of the intended method for validating\r\nsuch descriptions. Thanks to the independent nature among tasks\r\nrelated to different business services, represented by restrictions\r\nin the information flow within the metamodel, the state-space\r\nmay be fractioned for analysis, avoiding the state-space explosion\r\nproblem. Related existing models are discussed, pointing the gain\r\nin expressiveness of business rules and the analysis of insecure\r\nstate paths rather than simply insecure states in the proposed\r\nmodel. The successful representation and analysis of the policy\r\nfrom the example combined with reasonings for the general case\r\nattest the adequacy of the proposed approach for its intended\r\napplication....
Enterprise Resource Planning systems are a critical component nowadays of any private company or\r\npublic institution. Because of their complexity and their importance to all the core functions of an organization,\r\nsecurity represents a major concern that�s often overlooked besides the standard set-up. In this paper I will\r\nexplain the architecture of Oracle E-Business Suite, one of the most widely spread ERP solutions, its security\r\nproblems and an approach to solving them, hardening and customizing an Oracle E-Business Suite Application....
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