Ender Yüksel

A Secure Key Establishment Protocol for ZigBee Wireless Sensor Networks

ZigBee is a wireless sensor network standard that defines network and application layers on top of IEEE 802.15.4s physical and medium access control layers. In the latest version of ZigBee, enhancements are prescribed for the security sublayer but we show in this paper that problems persist. In particular, we show that the end-to-end application key establishment protocol is flawed and we propose a secure protocol instead. We do so by using formal verification techniques based on static program analysis and process algebras. We present a way of using formal methods in wireless network security, and propose a secure key establishment protocol for ZigBee networks.

Smart grid security a Smart Meter-centric perspective

The electricity grid is a key infrastructure for our society, therefore its security is a critical public concern. This physical system is becoming more and more complex as it is coupled with a cyber layer carrying information about power usage and control instructions for intelligent appliances, leading to what is known as the Smart Grid. The development of this Cyber-Physical System introduces new security issues, thus calling for efforts in studying possible attacks and devising suitable countermeasures. In this paper, we review a generic model for the Smart Grid, and present possible attacks and countermeasures focusing on a key component of the Smart Grid: the Smart Meter.

Security Games for Cyber-Physical Systems

The development of quantitative security analyses that consider both active attackers and reactive defenders is a main challenge in the design of trustworthy Cyber-Physical Systems. We propose a game-theoretic approach where it is natural to model attackers and defenders actions explicitly, associating costs to attacks and countermeasures. Cost considerations enable to contrast different strategies on the basis of their effectiveness and efficiency, paving the way to a multi-objective notion of optimality. Moreover, the framework allows expressing the probabilistic nature of the environment and of the attack detection process. Finally, a solver is presented to compute strategies and their costs, resorting to a recent combination of strategy iteration with linear programming.

Modelling and Analysis of Smart Grid: A Stochastic Model Checking Case Study

Cyber-physical systems integrate information and communication technology functions to the physical elements of a system for monitoring and controlling purposes. The conversion of traditional power grid into a smart grid, a fundamental example of a cyber-physical system, raises a number of issues that require novel methods and applications. In this context, an important issue is the verification of certain quantitative properties of the system. In this paper, we consider a specific Chinese Smart Grid implementation as a case study and address the verification problem for performance and energy consumption. We employ stochastic model checking approach and present our modelling and analysis study using PRISM model checker.

Optimizing key updates in sensor networks

Sensor networks offer the advantages of simple and low-resource communication. Nevertheless, security is of particular importance in many cases such as when sensitive data is communicated or tamper-resistance is required. Updating the security keys is one of the key points in security, which restrict the amount of data that may be exposed when a key is compromised. In this paper, we propose novel key update methods, and benefiting from stochastic model checking we propose a novel method for determining optimal key update strategies for custom network scenarios. We also present a case study where an application in commercial building automation is considered.

Quantitative modelling and analysis of a Chinese smart grid: a stochastic model checking case study

Cyber-physical systems integrate information and communication technology with the physical elements of a system, mainly for monitoring and controlling purposes. The conversion of traditional power grid into a smart grid, a fundamental example of a cyber-physical system, raises a number of issues that require novel methods and applications. One of the important issues in this context is the verification of certain quantitative properties of the system. In this paper, we consider a specific Chinese smart grid implementation as a case study and address the verification problem for performance and energy consumption. We employ stochastic model checking approach and present our modelling and analysis study using PRISM model checker.

Key Update Assistant for resource-constrained networks

Key update is a challenging task in resource-constrained networks where limitations in terms of computation, memory, and energy restrict the proper use of security mechanisms. We present an automated tool that computes the optimal key update strategy for any given resource-constrained network. We developed a push-button solution - powered by stochastic model checking - that network designers can easily benefit from, and it paves the way for consumers to set up key update related security parameters. Key Update Assistant, as we named it, runs necessary model checking operations and determines the optimal key update strategy that satisfies given security and performance requirements.

A secure key establishment protocol for zigbee wireless sensor networks

ZigBee is a wireless sensor network standard that defines network and application layers on top of IEEE 802.15.4s physical and medium access control layers. In the latest version of ZigBee, enhancements are prescribed for the security sublayer but we show in this paper that problems persist. In particular we show that the End-to-End Application Key Establishment Protocol is flawed and we propose a secure protocol instead. We do so by using formal verification techniques based on static program analysis and process algebras. We present a way of using formal methods in wireless network security, and propose a secure key establishment protocol for ZigBee networks.

LBTool: A stochastic toolkit for leave-based key updates

Quantitative techniques have been successfully employed in verification of information and communication systems. However, the use of such techniques are still rare in the area of security. In this paper, we present a toolkit that implements transient analysis on a key update method for wireless sensor networks. The analysis aims to find out the probability of a network key being compromised at a specific time point, which result in fluctuations over time for a specific key update method called Leave-based key update. For such a problem, the use of current tools is limited in many ways such as rapidly constructing a compact formal model, computing the time point where the risk is maximum, or terminating the transient analysis after the fluctuations disappear and system stabilizes. Our toolkit, LBTool, is not only resolving the above-mentioned issues, but also demonstrating how to construct models in an analytical way and how to speed up the analysis by eliminating redundant computations. The toolkit can be generalized to other key update methods by replacing the analytical model construction.