Jef Maerien

LooCI: The Loosely-coupled Component Infrastructure

Creating and managing applications for Wireless Sensor Networks (WSNs) is complicated by large scale, resource constraints and network dynamics. Reconfigurable component models minimize these complexities throughout the application lifecycle. However, contemporary component based middleware for WSNs is limited by its poor support for distribution. This paper introduces the Loosely-coupled Component Infrastructure (LooCI), a middleware for building distributed component-based WSN applications. LooCI advances the state-of-the-art by cleanly separating distributed concerns from component implementation, supporting application-level interoperability between heterogeneous WSN platforms and providing compatibility testing of bindings at runtime. Together, these features promote the safe and efficient composition and reconfiguration of distributed WSN applications. We evaluate the performance of LooCI on three classes of sensor nodes and demonstrate that these features can be provided with minimal overhead in terms of computation, memory and message passing.

MASY: MAnagement of Secret keYs for federated mobile wireless sensor networks

Wireless Sensor Networks are becoming federated and mobile environments. These new capabilities pose a lot of new possibilities and challenges. One of these challenges is to create a secure environment to allow multiple trusted companies to share and merge their sensor network infrastructure. The most basic need for a secure environment is the deployment of key material. However, most current day research assumes pre-shared secrets between the sensor nodes of most, if not all, companies in a federation. These solutions are often not scalable nor mobile enough to meet realistic business requirements. Additionally, most key deployment protocols totally omit any connectivity with back-end infrastructure. This paper proposes a novel deployment protocol for the MAnagement of Secret keYs (MASY). MASY allows secure deployment of a key to a sensor node when it enters a previously unknown network. By off-loading the trust creation process to the resource-rich back-end infrastructure, the burden on the sensor nodes remains very limited.

Energy aware software evolution for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are subject to high levels of dynamism arising from changing environmental conditions and application requirements. Reconfiguration allows software functionality to be optimized for current environmental conditions and supports software evolution to meet variable application requirements. Contemporary software modularization approaches for WSNs allow for software evolution at various granularities; from monolithic re-flashing of OS and application functionality, through replacement of complete applications, to the reconfiguration of individual software components. As the nodes that compose a WSN must typically operate for long periods on a single battery charge, estimating the energy cost of software evolution is critical. This paper contributes a generic model for calculating the energy cost of the reconfiguration in WSN. We have embedded this model in the LooCI middleware, resulting in the first energy aware reconfigurable component model for sensor networks. We evaluate our approach using two real-world WSN applications and find that (i.) our model accurately predicts the energy cost of reconfiguration and (ii.) component-based reconfiguration has a high initial cost, but provides energy savings during software evolution.

SecLooCI: A comprehensive security middleware architecture for shared wireless sensor networks

Abstract WSNs are trending towards dynamic environments that enable multiple parties to concurrently deploy and exploit multiple applications on shared nodes. The node owners want to share their nodes’ capabilities in order to increase return on investment, provide value added services, and easily share sensor node services. These concepts drive an evolving view on the software support that is required to service all stakeholders. For example, trust establishment, access control and security policy enforcement must be addressed. The node middleware must be extended to enable such shared usage of nodes while ensuring security. This paper presents the SecLooCI WSN middleware, which enables secure multi-party interactions on top of resource constrained sensor nodes. A prototype implementation for AVR Ravens running the Contiki OS shows the feasibility of the model for this low power micro-controller class of devices. This demonstrates that resource constrained sensor nodes are able to support secure node sharing.

Access control in multi-party wireless sensor networks

Emerging real world WSNs seldom exist as single owner, single application, isolated networks, but instead comprise of sensor nodes owned by multiple parties. These sensors offer multiple services to users locally or across the Internet, and travel between multiple WSNs. However, users should only have access to a limited subset of services. Due to a need for direct interactions of users with nodes, authentication and authorisation at the node level is critical. This paper presents an access control infrastructure consisting of three parts: 1) an authentication protocol to ensure authenticity of messages, 2) a role based authorisation framework to perform access control, and 3) a user management service to enable user and permission management. A prototype implementation on the ContikiOS demonstrates the validity and feasibility of node local role based access control on low power micro-controllers.

FAMoS: a flexible active monitoring service for wireless sensor networks

Given the limited resources of wireless sensor network infrastructure, knowledge of the traffic generated by each node and service can be of great value. Yet, accounting and conveying this monitoring information in this low-resource infrastructure is challenging. Current monitoring solutions for wireless sensor networks either use passive monitoring, requiring a separate network, or focus only on detecting and debugging failures in the sensor network. This paper presents FAMoS: a flexible active monitoring service to collect wireless sensor network traffic volume and distribution data. The service is provided with limited overhead and is applicable in many contexts. Each node locally collects data about network traffic and then periodically transmits the data to a back-end for further analysis and processing. A prototype for the Contiki operating system is presented and evaluated in terms of runtime, memory and communication overhead.

SASHA: A Distributed Protocol for Secure Application Deployment in Shared Ad-Hoc Wireless Sensor Networks

Wireless ad-hoc sensor networks in industrial settings often consist of multiple independent parties, each owning a subset of the nodes. In order to reduce costs, minimize time to market and increase coverage and functionality, these parties must share the capabilities of their individual sensor nodes; this creates a multi-owner and multi-application environment that requires advanced and secure mechanisms to control the deployment and operation of sensor applications. Although there is clear demand like in transport & logistics, state-of-the-art on secure application deployment in WSNs is lacking support for this sharing of sensor nodes. This paper presents SASHA: a proof-of-concept protocol that enables lightweight and secure deployment of multiple applications on heterogeneously owned sensor nodes.

A Secure Multi-Application Platform for Vehicle Telematics

Contemporary vehicles offer an advanced telematics platform with multiple applications available such as electronic road tolling, emergency call, breakdown call, or route planning. Given the sensitivity of collected driver and vehicle data and the potential use of this data by third party applications, security mechanisms are needed to protect services as well as data. Although security has been investigated in recent telematics studies, they do not consider potentially malicious or erroneous third party applications. This paper presents a secure multi-application platform that is designed as a modular software architecture with security features to support availability, confidentiality and integrity; a proof-of-concept prototype was developed on state-of-the-art hardware and software.

Building blocks for secure multiparty federated wireless sensor networks

Wireless Sensor Networks are increasingly being deployed in enterprise scenarios involving multiple actors. The capabilities of sensors must be shared across many applications and sensors must cooperate across federations spanning administrative domains. This paper describes our efforts towards constructing federated wireless sensor systems. It leverages and details key building blocks designed to achieve federation and sharing: a component model with distributed event-based communication, a policy-driven control infrastructure for resources and communications, a deployment architecture and a mechanism to establish and propagate trust into the wireless sensor network. The building blocks focus on the specific and necessary in-network extensions, such as extensions to sensor run-time, middleware and programming abstractions, rather than the backend challenges. The combination of the building blocks creates a security middleware that supports multiparty federated sensor networks. An estimate of the total cost of federation in terms of footprint is provided and first experiences of application of the middleware are reported upon.