The public defense of Elena Lisova's doctoral thesis in Computer Science and Engineering

Doctoral thesis and Licentiate seminars

Datum: 2018-04-16
Tid: 13.15
Plats: Room Gamma, MDH Västerås

The public defense of Elena Lisova's doctoral thesis in Computer Science and Engineering will take place at Mälardalen University, room Gamma (Västerås Campus) at 13.15 on April 16, 2018.

Title: “Monitoring for Securing Clock Synchronization”.

Serial number: 256.

The faculty examiner is Professor Panos Papadimitratos, KTH Royal Institute of Technology, and the examining committee consists of Docent Elena Troubitsyna, Åbo Akademi University; PhD Henrik Lönn, Volvo Group; Docent Mikael Asplund, Linköping University.

Reserve; Docent Moris Behnam, Mälardalen University


There are many types of systems including industrial networks, Internet of Things (IoT), distributed control systems, services systems, etc. All systems regardless of their specifics have a communication part that enables data exchange between system entities and external entities. Today's commercial systems adopt heterogeneous solutions including a combination of wired and wireless communication. Usage of both technologies together brings benefits in terms of flexibility and reliability, however it also imposes new challenges, such as maintaining system security. One more trend today is interconnecting systems for the benefits of their cooperation, such as remote control from a fog, or data storage in a cloud. In such circumstances security of heterogeneous systems becomes paramount to address, as system interconnections and heterogeneity open up new vulnerabilities and impose new threats.

One of the most critical properties of such systems is related to timing. The majority of these systems have real-time requirements, and communication follows some kind of schedule.  For event-triggered communication, data freshness can be based on its timestamp, and consequently, to judge data validity and events precedence, nodes need to interpret the received timestamp based on its own time. Both conditions make clock synchronization an essential network asset. Therefore, the first step in securing such systems is an investigation of ways to breach clock synchronization. The next step is development of a solution that allows detection of malicious influence in the system and mitigates the consequences.

In this thesis, the vulnerability analysis of clock synchronization is built upon the IEEE 1588 standard, widely used in industry for establishing and maintaining clock synchronization. A distributed monitoring is proposed as a way to detect if an adversary is influencing the clock synchronization in the network. Moreover, complementing distributed monitoring with peer-to-peer checks is also considered inorder to increase synchronization dependability. Game theory is used to investigate the interaction between an adversary and the monitor. The monitor strategy is based on dynamic rules of switching between network states. Furthermore, the time chase between an adversary and the monitor is investigated to see how the monitor strategy influences the outcome. Next, safety and security interaction is considered to see which implications the proposed solution can have on the safety domain. Finally, the design of a run-time monitor for a smart node, coping with unreliable communication is presented as a methodology. The methodology is applied to clock synchronization.