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Public defence in Communications Engineering, M.Sc.(Tech.) Jari Lietzen

Public defence from the Aalto University School of Electrical Engineering, Department of Information and Communications Engineering
Doctoral hat floating above a speaker's podium with a microphone

The title of the thesis: Secret Key Generation for Ambient Backscatter Communication

Doctoral student: M.Sc.(Tech.) Jari Lietzen
Opponent: Docent Aarne Mämmelä, VTT
Custos: Prof. Olav Tirkkonen, Aalto University School of Electrical Engineering, Department of Information and Communications Engineering 

The security of wireless Internet of Things (IoT) devices has become a concern. Therefore, sufficient protection against active eavesdropping or confusing devices with other users' devices is an essential requirement. Due to the embedded nature of these devices, they are often limited in their computational, communication and power resources. Ambient backscatter communication (AmBC) is seen as a viable solution for resource limited devices, as the wireless nodes are communicating without any active radio frequency components. 

In this thesis, we analyse secret key generation between ambient backscatter devices where the channel between an ambient transmitter and the backscatter devices is used as a source of randomness. Previous secret key generation methods have assumed that distance alone prevents the eavesdropper from having any information about the key prior to error correction. Our simulations show that a distance based approach is too optimistic, and there is a possibility that the eavesdropper still knows a substantial part of the final key. 

A working solution is based on a two-way key agreement protocol, and assuming that the eavesdropper’s error rates are k times that of the legitimate users, with k < 1. This method gives the legitimate users the freedom to trade off between achievable key rate and the eavesdropper’s knowledge of the final key.

Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

Contact information:

Doctoral theses in the School of Electrical Engineering: https://aaltodoc.aalto.fi/handle/123456789/53

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