Unconditionally secure authentication in quantum key distribution

Abstract EN

Quantum key distribution (QKD) is a method using some properties of quantum mechanics to create a secret shared cryptographic key even if an eavesdropper has access to unlimited computational power.

All QKD protocols require that the parties have access to an authentic channel.

Otherwise, QKD is vulnerable to man-in-the-middle attacks.

This paper studies QKD from this point of view, emphasizing the necessity and sufficiency of using unconditionally secure authentication in QKD.

In this work, a hybrid unconditionally secure authentication strategy is proposed for QKD protocols.

It is based on a mixture of normal application of authentication codes and the so-called "counter-based" authentication method such that to achieve a better trade off ■between security and efficiency (in terms of the required size of initially shared secret data).

Based on this strategy, a complete authenticated QKD protocol is described for a specific implementation of the well-known BB84 protocol.

Some advantages of our protocol in comparison to other proposals are also highlighted.