Authentication Through Error Estimation in QKD

The one-time pad is an encryption technique that is proven to be unbreakable by an eavesdropper. It relies on a secret key shared between the sender (Alice) and the receiver (Bob), with the same length as the message to be encrypted. Quantum Key Distribution (QKD) facilitates the telecommunication of such a shared secrete key between Alice and Bob. Its security is based on the laws of quantum physics: any eavesdropper (Eve) action can be statistically detected with very high probability. It requires a quantum channel for qubit transmission and a classical channel for transmission of some classical bits. The classical channel is usually authenticated by classical means, which are not theoretically proven to be completely secure for the ones used in practice. In this paper, we propose for the first time an authentication method for BB84-like QKD protocols that uses the error estimation of BB84 itself to authenticate both the classical channel and the quantum channel, using a pre-shared secret key with the one-time pad technique, and for which the security relies on both the information theory and the fundamental laws of quantum physics.