The Impact of Key Lengths on QKD Security

Abstract

Charles Bennett and Gilles Brassard, in 1984, proposed the first QKD protocol and called BB84. It is assumed the protocol shares a quantum key safely (between two parties). In 2000 it was implemented easily and showed a significant method for detecting an attacker that trying to get the shared key by utilizing the final key length. When the length exceeds a certain value, that is calculated before the transmitting the key, the majority of prior works agree with that, but this chapter showed a significant threat that affects the final key to same. There is no attacker at the middle. Moreover, this chapter analyzed the final key lengths and showed the harmed value of the final key length with the attacker effect. It also showed how often these values could be within the threshold. Furthermore, a solution was found to detect the attacker by using a machine learning technique. The results showed a promising accuracy to detect the attacker relying on the final key length.