Adaptive and reliable multi-hop over the air reprogramming of wireless sensor networks with fountain codes

Wireless sensor networks (WSN) represent an emerging set of technologies that will have profound effects across a wide range of industrial, scientific and governmental applications. In the civilian sector, probably the largest WSNs currently discussed are for critical infrastructure protection (CIP) like oil- and gas-pipelines, power distribution networks or nuclear power plants, with mesh networks spanning over kilometers. Once deployed, sensor nodes may need to be re-programmed either to remove bugs or to add new functionalities. In a real-world deployment of a WSN, the manual update of a code image via a physical interface is not really option, as its operation cost is too high. The most efficient way to do this is over the radio. However,a code image update over the wireless is critical regarding various aspects: Firstly, a multicast transmission of a relatively large data stream over a noisy, unreliable channel causes re-transmission of lost packets and can easily build up to an energy-wasting undesirable endless process. Secondly, over-the-air (OTA) programming is vulnerable to a multitude of passive and active attacks, and could offer a vector of attack to spread virus and malware to the whole network.

In this presentation, we would present a secure and adaptive over-the-air reprogramming tool for WSN based on fountain code technique. We argue that rateless ersure codes are only promising for OTA programming in conjunction with proper security enhancements such that bogus data can be verified on-the-fly and thus are not able to infect other received data. Moreover, we show the application of a fuzzy controller to throttle the propagation in order to adapt to the network conditions in a timely fashion. If there is enough time, a demonstration of the reprogramming tool will be shown at the end. Its performance will be compared with Deluge, another reprogramming tool.

Short biography: Alban Hessler obtained his master's degree in Communication Systems at the Swiss Institute of Technology of Lausanne (EPFL) in 2006. After written his master thesis at NEC Network Labs in Heidelberg on a context-aware recommender system, he joined the security research team in the same laboratory. Since then, he has been working in European projects which are dedicated to provide a secure and reliable architecture for wireless sensor networks.

Participatory Sensing in Commerce: Using Mobile Camera Phones to Track Market Price Dispersion

Empirical evidence suggests that price dispersion of homogenous goods in both online and offline markets is sizeable, pervasive, and persistent. Not surprisingly, there exist several popular web commerce sites such as Froogle that enable users to track consumer pricing information in online markets. In this talk, we present and explore our vision that participatory sensing can be employed in this new application domain to track price dispersion in homogeneous consumer goods even in offline markets. Participatory sensing enables collection and dissemination of environmental sensory data by ordinary citizens, through devices such as mobile phones, without requiring any pre-installed infrastructure. In this talk, we describe in detail one such proof-of-concept participatory sensing system that we have built called PetrolWatch for automated collection of fuel prices. In our proposed system, cameras of contributing users are automatically triggered to take pictures of the fuel price billboards when they get close to a service station. These images are then processed by computer vision algorithms to extract the fuel prices. Our system achieves a hit rate of 92.3% for correctly detecting the fuel price board from the image background and reads the prices correctly in 87.7% of them.

Short biography: Salil Kanhere received the BE degree in electrical engineering from the University of Bombay, Bombay, India in 1998 and the MS and PhD degrees in electrical engineering from Drexel University, Philadelphia, USA in 2001 and 2003, respectively. Since 2004, he is a faculty member with the School of Computer Science and Engineering at the University of New South Wales, Sydney, Australia. His current research interests include people-centric sensing, mobile networks and mesh networks.

Security by Wireless - or - Why Play Fairer than the Attacker?

Security in wireless networks is a notorious problem, suffering from  the following dilemma: On the one hand the wireless medium access puts the attacker into a much better position, on the other hand wireless  devices most often have resource deficiencies (processing, memory, energy) which make conventional attack countermeasures based on cryptographic solutions impractical. Though, there have been many approaches towards  lightweight security for wireless networks, this dilemma always persists, at  least for the low-cost sector, say, for example, sensor networks or RFIDs.

So far the overwhelming majority of wireless security approaches  followed a conventional security paradigm which abstracts the physical  communication as a logical channel. We depart from this paradigm, and try to  leverage from the physical characteristics of wireless communications as much as possible, thus bringing us again in equality of arms with the attacker. This  we coined the security by wireless principle. In the talk, several incarnations of the security by wireless  principle are presented. These are taken from WLAN as well as wireless sensor network scenarios and show for different security goals that  security by wireless designs can lead to interesting security solutions.

Short biography: Ivan Martinovic received his Diploma degree (equivalent to M.Sc.) in  computer science in 2003 from the University of Technology Darmstadt. In  2008, he received his Doctoral degree (Dr.-Ing.) from the University of  Kaiserslautern. His research interests are in the area of network security and applied cryptography. In particular, design and performance analysis of  lightweight security protocols for wireless networks. Currently, he is a postdoc researcher at the University of Kaiserslautern supported by Carl-Zeiss foundation scholarship.

Stream-oriented Lossless Data Compression in Wireless Sensor Networks

In wireless sensor networks, the energy consumption of participating nodes has crucial impact on the resulting network lifetime. Data compression is a viable approach towards preserving energy by reducing packet sizes and thus minimizing the activity periods of the radio transceiver. In this paper, we propose a compression framework utilizing a stream-oriented compression scheme for sensor networks. It is specifically tailored to the capabilities of employed nodes and network traffic characteristics, which we determine in a characterization of WSN traffic patterns. To mitigate the inapplicability of traditional compression approaches, we present the Squeeze.KOM compression layer. By shifting data compression into a dedicated layer, only minor modifications to applications are required, while efficient data transfer between nodes is provided. As a proof-of-concept, we implement a stream-based compression algorithm on sensor nodes and perform an experimental analysis to determine the potential gains under realistic traffic conditions. Results indicate that our presented lossless stream-oriented payload compression leads to considerable savings.

Short biography: Andreas Reinhardt received his Diploma degree in Electrical Engineering and Information Technology from Technische Universität Darmstadt in 2007. His diploma thesis addresses the development of a debugging system for reconfigurable wireless sensor network nodes. In December 2007, he joined the Multimedia Communication Lab (KOM) at TU Darmstadt, where he now investigates means to integrate wireless sensor networks into context-aware communication systems.

Sensor Network Calculus - Motivation, Basics, Applications

In this talk, I will present a methodology called sensor network calculus. The sensor network calculus allows to model sensor networks and perform worst- or bad-case analyses. Based on such an analytical framework a plethora of network design and control problems can be tackled. I will briefly present the underlying foundations of the network calculus as well as its customization towards wireless sensor networks. Some interesting open theoretical problems will be identified, before we delve into a number of representative applications of the theory such as buffer dimensioning, duty cycle sizing, and sink placement to illustrate the versatility of sensor network calculus.

Short biography: Jens Schmitt is professor for Computer Science at the TU Kaiserslautern. Since 2003 he has been the head of the Distributed Computer Systems Lab (disco). His research interests are broadly in performance and security aspects of networked and distributed systems. He received a PhD from TU Darmstadt in 2000.

A ROM-friendly Secure Code Update mechanism for WSNs using a stateful-verifier T-time Signature Scheme

Several mechanisms have been proposed to efficiently authenticate multicast of finite data streams as needed for code image updates in wireless sensor networks (WSNs). They involve either a public-key digital signature or loose time synchronization between the sender and the receivers. What usually does not get any attention is the program memory (ROM) occupied by these mechanisms which do not fulfill the primary task of a sensor network. An optimized implementation of the elliptic curve digital signature scheme occupies up to 25% of the ROM of a TelosB node; the same or even more is needed for time synchronization schemes. Therefore, if sensor networks do not need public-key operations or time synchronization for their primary task, these SCU mechanism are not suitable for coexistence with the application code on the sensor nodes. This work contributes in two directions. Firstly, we propose a stateful-veri_er T –time signature scheme based on Merkle's one-time signature. Secondly, we propose a protocol exploiting our signature scheme for securing existing code image update protocols for WSNs minimizing ROM overhead to 1% on TelosB motes.

Short biography: Osman Ugus received his Diplom degree in 2007 from Technische Universität Darmstadt with a focus on IT-security. His diploma thesis deals with analysis and the implementation of public key cryptography primitives on embedded systems with limited hardware capabilities such as sensor platforms. In April 2007, he joined NEC Europe Network Laboratories as a resource associate. He is interested in security and lightweight cryptography especially in wireless sensor networks.

FAIR: Fuzzy based Aggregation providing In-network Resilience for real-time Wireless Sensor Networks

This work introduces FAIR, a novel framework for Fuzzy-based Aggregation providing In-network Resilience for wireless sensor networks (WSN). FAIR addresses the possibility of malicious aggregator nodes manipulating sensed and aggregated data. It provides data-integrity based on a trust level of the WSN response and it tolerates link or node failures. Compared to available solutions, it overhears a general aggregation model and makes the trust level visible to the querier. We classify the proposed approach as complementary to protocols providing resilience against sensor leaf nodes providing faulty data. Thanks to our flexible resilience framework and due to the use of Fuzzy Control techniques we achieved promising results during a short design cycle.

Short biography: Dirk Westhoff received the Ph.D. degree in computer science in 2000 and in 2007 his postdoctoral lecture qualification entitled "Security and Dependability Solutions for 4G Wireless Access Networks", both from the Distance University of Hagen. Since 2001 he is at NEC Europe Ltd. R&D Network Laboratories in Heidelberg, Germany, currently as a chief researcher. Recently Dirk Westhoff has been strongly involved in the definition and launching phases of the European projects UbiSec&Sens, SENSEI and WSAN4CIP. He is co-founder of the ESAS (European Workshop on Security in Ad Hoc and Sensor Networks) series published by Springer.  He has more than 60 peer-reviewed publications in network security and distributed system's security and he holds seven patents. He has been involved in the TPC of several ACM and IEEE workshops and conferences and he is a member of the Steering Committee of the ACM WiSec. His research interests include wireless security, ad hoc and sensor network security, and many other security and privacy aspects of distributed mobile communication.