Lawrence M. Ioannou

Public-key cryptography has proved to be an indispensable tool in the modern information security infrastructure. We prove that an identification scheme based on bounded quantum reference frames is secure against a computationally-unbounded adversary (only restricted by finite cheating strategies), demonstrating for the first time that unconditionally-secure and reusable public-key authentication is possible in principle. To prove security of our protocol, we employ elements of the polynomial method, the theory of estimation of black-box group transformations, and the theory of bounded quantum reference frames. We also use the quantum Fourier transform in a new and rather surprising way.