Paper 2004/156

Quantum cryptography: a practical information security perspective

Kenneth G. Paterson and Fred Piper and Ruediger Schack

Abstract

Quantum Key Exchange (QKE, also known as Quantum Key Distribution or QKD) allows communicating parties to securely establish cryptographic keys. It is a well-established fact that all QKE protocols require that the parties have access to an authentic channel. Without this authenticated link, QKE is vulnerable to man-in-the-middle attacks. Overlooking this fact results in exaggerated claims and/or false expectations about the potential impact of QKE. In this paper we present a systematic comparison of QKE with traditional key establishment protocols in realistic secure communication systems.

Note: This paper was originally posted with the title "Why quantum cryptography?" It was published in Quantum Communication and Security, Proceedings, NATO Advanced Research Workshop, edited by M. ˙Zukowski, S. Kilin and J. Kowalik, p. 175–180 (IOS Press, Amsterdam, 2007).