MRD hashing

We propose two new classes of hash functions which are motivated by Maximum Rank Distance (MRD) codes. We analise the security of these schemes. The system setup phase is computationally expensive for general field extensions. To overcome this limitation we derive an algebraic solution which avoids computations in special extension fields in the intended operational range of the hash functions.

Lightweight authentication for recovery in wireless sensor networks

Wireless sensor networks (WSNs) suffer from a wide range of security attacks due to their limited processing and energy capabilities. Their use in numerous mission critical applications, however, requires that fast recovery from such attacks be achieved. Much research has been completed on detection of security attacks, while very little attention has been paid to recovery from an attack. In this paper, we propose a novel, lightweight authentication protocol that can secure network and node recovery operations such as re-clustering and reprogramming. Our protocol is based on hash functions and we compare the performance of two well-known lightweight hash functions, SHA-1 and Rabin. We demonstrate that our authentication protocol can be implemented efficiently on a sensor network test-bed with TelosB motes. Further, our experimental results show that our protocol is efficient both in terms of computational overhead and execution times which makes it suitable for low resourced sensor devices.

A serverless ultra-lightweight secure search protocol for EPC Class-1 Gen-2 UHF RFID tags

Radio Frequency Identification (RFID) is a technology that enables the non-contact, automatic and unique identification of objects using radio waves. Its use for commercial applications has recently become attractive with RFID technology seen as the replacement for the optical barcode system that is currently in widespread use. RFID has many advantages over the traditional barcode and these advantages have the potential to significantly increase the efficiency of decentralised business environments such as logistics and supply chain management. One of the important features of an RFID system is its ability to search for a particular tag among a group of tags. In order to ensure the privacy and security of the tags, the search has to be conducted in a secure fashion. To our knowledge not much work has been done in this secure search area of RFID. The limited work that has been done does not comply with the EPC Class-1 Gen-2 standards since most of them use expensive hash operations or sophisticated encryption schemes that cannot be implemented on low-cost passive tags that are highly resource constrained. Our work aims to fill this gap by proposing a serverless ultra-lightweight secure search protocol that does not use the expensive hash functions or any complex encryption schemes but achieves compliance with EPC Class-1 Gen-2 standards while meeting the required security requirements. Our protocol is based on XOR encryption and random numbers - operations that are easily implemented on low-cost RFID tags. Our protocol also provides additional protection using a blind-factor to prevent tracking attacks. Since our protocol is EPC Class-1 Gen-2 compliant it makes it possible to implement it on low-cost passive RFID tags.

A secure search protocol based on Quadratic Residues for EPC Class-1 Gen-2 UHF RFID tags

Radio Frequency Identification (RFID) is a technological revolution that is expected to soon replace barcode systems. One of the important features of an RFID system is its ability to search for a particular tag among a group of tags. This task is quite common where RFID systems play a vital role. To our knowledge not much work has been done in this secure search area of RFID. Also, most of the existing work do not comply with the C1G2 standards. Our work aims to fill that gap by proposing a protocol based on Quadratic Residues property that does not use the expensive hash functions or any complex encryption schemes but achieves total compliance with industry standards while meeting the security requirements.

Offline grouping proof protocol for RFID systems

Several grouping proof protocols have been proposed over the years but they are either found to be vulnerable to certain attacks or do not comply with EPC Class-1 Gen-2 (C1G2) standard because they use hash functions or other complex encryption schemes. Also, synchronization of keys, forward security, proving simultaneity, creating dependence, detecting illegitimate tags, eliminating unwanted tag processing and denial-of-proof (DoP) attacks have not been fully addressed by many. Our protocol addresses these important gaps and is based on Quadratic Residues property where the tags are only required to use XOR, 128-bit Pseudo Random Number Generators (PRNG) and Modulo (MOD) operations which can be easily implemented on low-cost passive tags and hence achieves EPC C1G2 compliance.

RFID tags : grouping proof with forward security

Several grouping proof protocols have been proposed over the years but they are either found to be vulnerable to certain attacks or do not comply with EPC Class-1 Gen-2 (C1G2) standard because they use hash functions or other complex encryption schemes. Among other requirements, synchronization of keys, forward security, dependence, detecting illegitimate tags, eliminating unwanted tag processing and denial-of-proof (DoP) attacks have not been fully addressed by many. Our protocol addresses these important gaps and is based on simple XOR encryption and 128-bit Pseudo Random Number Generators (PRNG), operations that are easily implemented on low-cost passive tags and hence achieves EPC C1G2 compliance.

A robust grouping proof protocol for RFID EPC C1G2 tags

Several grouping proof protocols for RFID systems have been proposed over the years but they are either found to be vulnerable to certain attacks or do not comply with the EPC class-1 gen-2 (C1G2) standard because they use hash functions or other complex encryption schemes. Among other requirements, synchronization of keys, simultaneity, dependence, detecting illegitimate tags, eliminating unwanted tag processing, and denial-of-proof attacks have not been fully addressed by many. Our protocol addresses these important gaps by taking a holistic approach to grouping proofs and provides forward security, which is an open research issue. The protocol is based on simple (XOR) encryption and 128-bit pseudorandom number generators, operations that can be easily implemented on low-cost passive tags. Thus, our protocol enables large-scale implementations and achieves EPC C1G2 compliance while meeting the security requirements.

Zero knowledge grouping proof protocol for RFID EPC C1G2 Tags

In this paper, we propose a novel zero knowledge grouping proof protocol for RFID Systems. Over the years, several protocols have been proposed in this area but they are either found to be vulnerable to certain attacks or do not comply with the EPC Class 1 Gen 2 (C1G2) standard because they use hash functions or other complex encryption schemes. Also, the unique design requirements of grouping proofs have not been fully addressed by many. Our protocol addresses these important security and design gaps in grouping proofs. We present a novel approach based on pseudo random squares and quadratic residuosity to realize a zero knowledge system. Tag operations are limited to functions such as modulo (MOD), exclusive-or (XOR) and 128 bit Pseudo Random Number Generators (PRNG). These can be easily implemented on passive tags and hence achieves compliance with the EPC Global standard while meeting the security requirements.

Filtering redundant data from RFID data streams

Radio Frequency Identification (RFID) enabled systems are evolving in many applications that need to know the physical location of objects such as supply chain management. Naturally, RFID systems create large volumes of duplicate data. As the duplicate data wastes communication, processing, and storage resources as well as delaying decision-making, filtering duplicate data from RFID data stream is an important and challenging problem. Existing Bloom Filter-based approaches for filtering duplicate RFID data streams are complex and slow as they use multiple hash functions. In this paper, we propose an approach for filtering duplicate data from RFID data streams. The proposed approach is based on modified Bloom Filter and uses only a single hash function. We performed extensive empirical study of the proposed approach and compared it against the Bloom Filter, d-Left Time Bloom Filter, and the Count Bloom Filter approaches. The results show that the proposed approach outperforms the baseline approaches in terms of false positive rate, execution time, and true positive rate.

Molecular basis of copper transport: cellular and physiological functions of Menkes and Wilson disease proteins (ATP7A and ATPB)

Eukaryotic cells prevent copper-induced, free radical damage to cell components by employing copper-binding proteins and transporters that minimize the likelihood of free copper ions existing in the cell. In the cell, copper is actively transported from the cytoplasm during the biosynthesis of secreted coppercontaining proteins and, as a protective measure, when there is an excess of copper. In humans, this is accomplished by two related copper-transporting ATPases (ATP7A and ATP7B), which are the affected genes in two distinct human genetic disorders of copper transport, Menkes disease (copper deficiency) and Wilson disease (copper toxicosis). The study of these ATPases has revealed their molecular mechanisms of copper transport and their roles in physiological copper homeostasis. Both ATP7A and ATP7B are expressed in specific brain regions and neurological abnormalities are important clinical features in Menkes and Wilson disease.

Comparison of Two Methods for Caluculating the Partition Functions of Various Spatial Statistical Models

Likelihood computation in spatial statistics requires accurate and efficient calculation of the normalizing constant (i.e. partition function) of the Gibbs distribution of the model. Two available methods to calculate the normalizing constant by Markov chain Monte Carlo methods are compared by simulation experiments for an Ising model, a Gaussian Markov field model and a pairwise interaction point field model.

Interpolation of Lipschitz functions

This paper describes a new computational approach to multivariate scattered data interpolation. It is assumed that the data is generated by a Lipschitz continuous function f. The proposed approach uses the central interpolation scheme, which produces an optimal interpolant in the worst case scenario. It provides best uniform error bounds on f, and thus translates into reliable learning of f. This paper develops a computationally efficient algorithm for evaluating the interpolant in the multivariate case. We compare the proposed method with the radial basis functions and natural neighbor interpolation, provide the details of the algorithm and illustrate it on numerical experiments. The efficiency of this method surpasses alternative interpolation methods for scattered data.

A comparison of search functions and other navigational tools provided on government websites

This paper reports the outcomes of a study that evaluated the effectiveness of search functions compared to other navigational tools available on government websites. The study used an observation exercise triangulated with a post observation interview. Results suggest that while there wasn't any significant difference in effectiveness between search functions and other navigational tools, the skill with which the search function is implemented and participants' familiarity with the website, are fundamental determinants of users' opinions. Implications of the findings for research and practice are discussed.