The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Device-to-device communication underlaying a cellular network is a promising technology in future wireless networks to improve network capacity and user experience. While D2D communication has great potential to improve wireless system spectral and energy efficiency due to the proximity of communication parties and higher spectrum reuse gain, tremendous work is still ongoing to turn the promising technology into a reality. This article discusses D2D technical challenges as well as standards progress and important research aspects that enable D2D communications underlaying cellular networks. The key research areas addressed include interference management, multihop D2D communications, and D2D communications in heterogeneous networks. When enabling D2D communications underlaying cellular networks, D2D communications can use either cellular downlink or cellular uplink resources. The two resource sharing modes will create different interference scenarios. The performance evaluation on D2D communications underlaying cellular networks under these two different scenarios is provided.

Enable device-to-device communications underlaying cellular networks: challenges and research aspects

In this paper, we present an in-depth study of two collaborative-localization methods, called the multidimensional scaling (MDS) and maximum-likelihood estimator (MLE), for wireless sensor networks. From theoretical analysis, it is shown that MLE is more appropriate than MDS, given the underlying assumption of statistical signal models of the received-signal-strength-based localization problem. We also show that MDS can approximately achieve asymptotic efficiency with appropriate weighting schemes in some scenarios. From extensive simulation results, it is noted that the nonlinear least square algorithms that are commonly used to determine MLE are not as efficient as the iterative MDS algorithms. Thus, we propose a new integrated method MDS-MLE to effectively benefit from the strength of both methods. In the new method, MDS is used as an initialization method for MLE. With the solution of MDS as an initial value, MLE converges much faster and achieves significantly better performance than with random initial values. Superior performance of the new method is clearly demonstrated through simulation results. The effects of the deployment density of sensor nodes and reference nodes (RNs), as well as the deployment structure of RNs, are also studied through various simulations.

Collaborative Localization With Received-Signal Strength in Wireless Sensor Networks

Association rule extraction from operational datasets often produces several tens of thousands, and even millions, of association rules. Moreover, many of these rules are redundant and thus useless. Using a semantic based on the closure of the Galois connection, we define a condensed representation for association rules. This representation is characterized by frequent closed itemsets and their generators. It contains the non-redundant association rules having minimal antecedent and maximal consequent, called min-max association rules. We think that these rules are the most relevant since they are the most general non-redundant association rules. Furthermore, this representation is a basis, i.e., a generating set for all association rules, their supports and their confidences, and all of them can be retrieved needless accessing the data. We introduce algorithms for extracting this basis and for reconstructing all association rules. Results of experiments carried out on real datasets show the usefulness of this approach. In order to generate this basis when an algorithm for extracting frequent itemsets--such as Apriori for instance--is used, we also present an algorithm for deriving frequent closed itemsets and their generators from frequent itemsets without using the dataset.

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Generating a Condensed Representation for Association Rules

Radio frequency identification and wireless sensor networks are two important wireless technologies that have a wide variety of applications in current and future systems. RFID facilitates detection and identification of objects that are not easily detectable or distinguishable by using conventional sensor technologies. However, it does not provide information about the condition of the objects it detects. WSN, on the other hand, not only provides information about the condition of the objects and environment but also enables multihop wireless communications. Hence, the integration of these technologies expands their overall functionality and capacity. This article investigates recent research work and applications that integrate RFID with sensor networks. Four classes of integration are discussed: integrating tags with sensors, integrating tags with WSN nodes and wireless devices, integrating readers with WSN nodes and wireless devices, and a mix of RFID and WSNs. Finally, a discussion of new challenges and future work is presented.

Taxonomy and Challenges of the Integration of RFID and Wireless Sensor Networks

Transactions on knowledge and data engineering

In wireless ad-hoc networks, a major challenge is how to provide robust and efficient communication. To achieve this goal, cooperative communication and network coding have been proven to be effective. In the literature, most existing studies focus on the performance of the two schemes separately. In our study, we will investigate the performance of system that combines them tightly together. In particular, we will propose a unified two-way traffic model that can characterize the features of both of them. Based on this model, we develop a new cooperative network coding scheme to further improve the system throughput. Both decode-and-forward and amplify-and-forward techniques are discussed for the two-way traffic model. Numerical results show that the new scheme can significantly improve the performance over traditional schemes.

Cooperative Network Coding for Wireless Ad-Hoc Networks

Sensor-Embedded Radio Frequency Identification (SE-RFID) is introduced to enhance the sensing functions of the current RFID systems. Two innovative architectures for SE-RFID systems are proposed and analyzed; the preliminary simulation of the proposed SE-RFID systems based on EDA software has been conducted successfully. An effort to design, simulate and develop a real-time Health Monitoring System (HEMS) based on SE-RFID is now under way.

Design of Sensor-Embedded Radio Frequency Identification (SE-RFID) Systems

In this paper we present a high-performance, high throughput, and area efficient architecture for the VLSI implementation of the AES algorithm. The subkeys, required for each round of the Rijndael algorithm, are generated in real-time by the key-scheduler module by expanding the initial secret key, thus reducing the amount of storage for buffering. Moreover, pipelining is used after each standard round to enhance the throughput. A prototype chip implemented using 0.35 /spl mu/ CMOS technology resulted in a throughput of 232Mbps for iterative architecture and 1.83Gbps for pipelining architecture.

A high-performance VLSI architecture for advanced encryption standard (AES) algorithm

In this paper, we present an innovative method of teaching digital system design in an undergraduate electrical and computer engineering curriculum. We present a project-based approach to teaching digital system design as opposed to the traditional method that uses conventional classroom lectures with short laboratory exercises. In our approach, students are exposed to a series of industrial-like, semester-long projects that cover fundamental topics in digital system design such as combinational circuit design, sequential circuit design, state machine design, etc. These projects are carried out in groups, thereby developing the students' abilities to work in teams. We present evidence that this project approach offers benefits such as increased student interest and better retention. Currently, 62 percent of our senior design projects are directly related to the concepts presented in this innovative course.

Murali Varanasi

Papers

Transactions on knowledge and data engineering

Cooperative Network Coding for Wireless Ad-Hoc Networks

Design of Sensor-Embedded Radio Frequency Identification (SE-RFID) Systems

A high-performance VLSI architecture for advanced encryption standard (AES) algorithm

An innovative method of teaching digital system design in an undergraduate electrical and computer engineering curriculum