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  Industrial CASE PhD Studentship on Implementation Security of Quantum Cryptosystems

   PhD Studentships

  Dr James Dynes  Applications accepted all year round  Funded PhD Project (Students Worldwide)

About the Project

There is currently great interest in using quantum communications to secure telecom networks, as well as to link quantum processors together to build a distributed quantum computer. Quantum communications such as Quantum Key Distribution (QKD) at TEUR is based on the transmission of single photons through an optical channel, such as an optical fibre.  Quantum mechanics provides security through the ability to detect eavesdropping which is not possible in conventional asymmetric key sharing schemes. Furthermore, security in QKD can be quantified through the security parameter. TEUR’s proprietary QKD protocol known as T12 has an associated security parameter of around 10-10 which roughly translates into one key “failure” in 30,000 years [1].

Faithful implementation of the protocol in the QKD system is of paramount importance to guarantee the security parameter. If there are gaps between the protocol and the implementation then these differences can produce side-channels which an adversary can exploit to learn the content of the shared secret key. Common QKD side-channels can lead to attacks such as Trojan horse attacks [2] on the encoding and decoding modulators in the QKD transmitter and receiver respectively and single photon detector blinding. Identifying these side-channels and coming up with appropriate countermeasures is normally referred to as the topic of Implementation Security. Over the years TEUR has played a key role in plugging these side-channels [3 – 5]. Furthermore TEUR is currently involved in implementation security standardisation work both in Europe and Japan. The resulting standards will provide criteria which QKD systems should adhere to so they can be formally security certified by appropriate test laboratories.

A PhD project is available based at Toshiba Europe Ltd, in collaboration with the University of York, which focuses on enhancing the security of quantum key distribution (QKD) systems. The project involves designing and implementing new techniques to improve the security of QKD systems. The candidate will also evaluate the performance of optical and electronic components and apply these techniques to a QKD system prototype. This project offers an opportunity to contribute to the development of cutting-edge QKD security techniques and gain expertise in the field of optical characterisation and security enhancement

This work will involve extensive experimental research, combining both high-speed optical and electronic devices, in addition to developing new software for implementing countermeasures. It is expected that the candidate will develop broad expertise with semiconductor lasers, pulse generation, optical modulation, high-speed RF electronics, fibre optics, quantum photonics, quantum information science, and single-photon photo-detection. There are also opportunities for the experimental work to be underpinned by theoretical studies to simulate and optimise the underlying quantum communication protocols.

Computer Science (8) Engineering (12) Physics (29)


[1] “Efficient decoy-state quantum key distribution with quantified security,” M. Lucamarini et al. Opt. Express, 21 24550 (2013)
[2] “Practical Security Bounds Against the Trojan-Horse Attack in Quantum Key Distribution,” M. Lucamarini et al. Phys. Rev. X, 5, 031030 (2015)
[3] “Quantum key distribution with hacking countermeasures and long term field trial,” A. R. Dixon et al. Sci. Rep., 7, 1978 (2017)
[4] " Testing the photon-number statistics of a quantum key distribution light source,” J. F. Dynes et al. (2018) Opt. Express, 26 22733 (2018)
[5] “Best-Practice Criteria for Practical Security of Self-Differencing Avalanche Photodiode Detectors in Quantum Key Distribution,” A. Koehler-Sidki et al. Phys. Rev. Applied, 9 044027 (2018)