Project 3: Phase encrypted continuous variable quantum communications and hybrid quantum cryptography

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Host Institute: Telecom ParisTech

Project Supervisor: Dr Romain Alléaume

ESR: Nilesh Vyas

Tentative placements/visits arranged at: University of Leeds, University of Vigo, Toshiba Research Europe Ltd, University of Geneva

Starting date: August 2017

Duration: 3 years

Project Description

A PhD position is available to investigate a new direction in quantum cryptography, in which computational assumptions are used to boost the performance of quantum cryptographic protocols. The aim of the research will consists in studying and experimentally demonstrating quantum cryptographic protocols that exhibit everlasting security, unachievable by classical means, and yet that partially rely on the power of computational cryptography, used to perform phase encryption. The security of  such hybrid quantum cryptographic protocols can be defined in a framework where one assumes that decoherence of quantum memories is bound to occur before computational encryption can be broken  (“encryption stronger than quantum noisy memory” = esquimo). In this context, high-dimensional quantum encoding can be used to enhance the rate and to cover longer distances than what is allowed with standard QKD [QCrypt2015, Hot topics session talk 3].

The first objective of this PhD project will be to demonstrate how the aforementioned hybrid approach can be used to push forward the performance and also the applicability of quantum cryptography. A first milestone will consist in developing proof techniques adapted for such hybrid key distribution protocols, based on ideas from [Phys. Rev. A 82, 022326, 2010]. Protocols beyond key distribution, and in particular untrusted relaying and quantum public-key encryption will also be investigated. The second objective, conducted in collaboration with a post-doctoral researcher, will consist in developing an experimental demonstration in the laboratory. We will in particular develop a set-up to perform quantum communication over a large number of modes (high dimension), based on continuous-variable quantum communication tools.

Project Outcomes

To be updated.