Vladimir A. Oleshchuk

Spatial role-based access control model for wireless networks

Role-based access control has established itself as a generalized approach for handling access control in large corporate systems. In wireless computing environments, the availability of roles and permissions may depend on a users location. To cope with the spatial requirements, we extend the existing RBAC model and propose a spatial role-based access control (SRBAC) model that utilized location information in security policy definitions.

Ontology based semantic similarity comparison of documents

In this paper, we consider ontologies as knowledge structures that specify terms, their properties and relations among them to enable knowledge extraction from texts. We represent ontologies using a graph-based model that reflect semantic relationship between concepts and apply them to text analysis and comparison. Instead of raw document comparison we compare document footprint enhanced with concepts from the ontology (using different enhancement algorithms). The result of this process may be that documents not similar prior to the enhancement become similar (semantically on some abstraction level) after the enhancement. This is because the enhancement process may introduce in the document footprint abstract concepts from the ontology. Using the ontology we can enhance the foot-prints by adding concepts that are not present in the original document. We may use synonyms for a horizontal expansion and broader terms/superclasses/types in a vertical expansion or both for that matter.

Remote Patient Monitoring Within a Future 5G Infrastructure

Systems of wearable or implantable medical devices (IMD), sensor systems for monitoring and transmitting physiological recorded signals, will in future health care services be used for purposes of remote monitoring. Today, there exist several constraints, probably preventing the adoption of such services in clinical routine work. Within a future 5G infrastructure, new possibilities will be available due to improved addressing solutions and extended security services in addition to higher bandwidth in the wireless communication link. Thus 5G solutions can represent a paradigm shift regarding remote patient’s monitoring and tracking possibilities, with enhancement in transmitting information between patients and health care services. Some aspects of new possibilities are highlighted in describing a realistic scenario within a future 5G framework.

A Novel Approach to Trust Management in Unattended Wireless Sensor Networks

Unattended Wireless Sensor Networks (UWSNs) are characterized by long periods of disconnected operation and fixed or irregular intervals between sink visits. The absence of an online trusted third party implies that existing WSN trust management schemes are not applicable to UWSNs. In this paper, we propose a trust management scheme for UWSNs to provide efficient and robust trust data storage and trust generation. For trust data storage, we employ a geographic hash table to identify storage nodes and to significantly decrease storage cost. We use subjective logic based consensus techniques to mitigate trust fluctuations caused by environmental factors. We exploit a set of trust similarity functions to detect trust outliers and to sustain trust pollution attacks. We demonstrate, through extensive analyses and simulations, that the proposed scheme is efficient, robust and scalable.

Conformance checking of RBAC policy and its implementation

The purpose a security policy is to specify rules to govern access to system resources preferably without considering implementation details. Both policy and its implementation might be altered, and after introducing changes, it is not obvious that they are consistent. Therefore, we need to validate conformance between policy and its implementation. In this paper we describe an approach based on finite-model checking to verify that a RBAC implementation conforms to a security policy. We make use of the model-checking system SPIN, and show how to express RBAC policy constraints by means of LTL and how to model an RBAC implementation in SPINs internal modeling language PROMELA.

Semantic retrieval: an approach to representing, searching and summarising text documents

Nowadays, the internet is the major source of information for millions of people. There are many search tools available on the net but finding appropriate text information is still difficult. The retrieval efficiency of the presently used systems cannot be significantly improved: ‘bag of words’ interpretation causes losing semantics of texts. We applied the functional approach to represent English text documents. It allows taking into account semantic relations between words when indexing documents and use ordinary English sentences as queries to a search engine. The proposed retrieval mechanisms return only highly relevant documents. They make it possible to generate content-aware summaries on-the-fly. The presented examples illustrate the advantage of the discussed approach compared to the traditional key word search.

Optimized secure and reliable distributed data storage scheme and performance evaluation in unattended WSNs

Unattended Wireless Sensor Networks (UWSNs), characterized by the absence of real-time communication between sensors and sinks, impose sensors to retain data till the next visit of a mobile sink to off-load their data. In such networks, if a sensor is compromised, data accumulated in the sensor are exposed to attackers. In addition, by holding the secret key of the compromised sensor, attackers can also learn post-compromise data accumulated by the sensor. Furthermore, once sensors stop working due to, for instance, node crash or battery depletion, all the accumulated data will be lost. In this paper, we propose a secure and reliable data distribution scheme that addresses these challenges. Detailed analysis shows that our scheme can provide forward secrecy, probabilistic backward secrecy and data reliability. To further improve probabilistic backward secrecy and data reliability, a constrained optimization data distribution scheme is also proposed. Detailed analysis and simulation results show the superiority of the proposed scheme in comparison with several existing schemes developed for UWSNs.

Security in Mobile Wireless Sensor Networks – A Survey

Thanks to recent advances in robotics, sensors and wireless communications, it is feasible to develop a variety of new architectures for Mobile Wireless Sensor Networks (MWSNs) that play an important role in various applications such as battlefield surveillance, harbor monitoring, etc. However, due to the dynamic of mobile network topology in MWSNs, many new security challenges have emerged. In this article, we give a survey on the state of the art technologies in security aspects of MWSNs. We review existing work that provides security in MWSNs, with an emphasis on data survival, forward secrecy, backward secrecy, authentication, and methods for sensor capture detection. Furthermore, in order to stimulate the exploration of new research areas, we point out a few open research topics that can be further pursued, and also shed light on these topics.

New client puzzle approach for DoS resistance in ad hoc Networks

In this paper we propose a new client puzzle approach to prevent Denial of Service (DoS) attacks in ad hoc networks. Each node in the network first solves a computational problem and with the solution has to create and solve a client puzzle. By combining computational problems with puzzles, we improve the efficiency and latency of the communicating nodes and resistance in DoS attacks. Experimental results show the effectiveness of our approach.

A Scheme for Secure and Reliable Distributed Data Storage in Unattended WSNs

Unattended Wireless Sensor Networks (UWSNs) operated in hostile environments face a risk on data security due to the absence of real-time communication between sensors and sinks, which imposes sensors to accumulate data till the next visit of a mobile sink to off-load the data. Thus, how to ensure forward secrecy, backward secrecy and reliability of the accumulated data is a great challenge. For example, if a sensor is compromised, pre-compromise data accumulated in the sensor is exposed to access. In addition, by holding key secrecy of the compromised sensor, attackers also can learn post-compromise data in the sensor. Furthermore, in practical UWSNs, once sensors stop working for accidents due to node crash or battery depletion, all the data accumulated will be lost. To address the challenges, we propose a secure and reliable data distribution scheme in this paper. Detailed analysis shows that our scheme can provide forward secrecy, probabilistic backward secrecy and data reliability. To further improve probabilistic backward secrecy and data reliability, a constrained optimization data distribution scheme is proposed. Detailed analysis and simulation results show the superiority of the proposed scheme in comparison with several previous approaches developed for UWSNs.