Lightweight Mediated Semi-Quantum Key Distribution Protocol with a Dishonest Third Party based on Bell States
This is an incremental improvement for secure communication between classical participants in quantum key distribution.
This study tackled the problem of mediated semi-quantum key distribution by proposing a protocol that eliminates the need for expensive Trojan horse detectors and allows for a dishonest third party, using Bell states to achieve security against known attacks with only two quantum capabilities.
The mediated semi-quantum key distribution (MSQKD) protocol is an important research issue that lets two classical participants share secret keys securely between each other with the help of a third party (TP). However, in the existing MSQKD protocols, there are two improvable issues, namely (1) the classical participants must be equipped with expensive detectors to avoid Trojan horse attacks and (2) the trustworthiness level of TP must be honest. To the best of our knowledge, none of the existing MSQKD protocols can resolve both these issues. Therefore, this study takes Bell states as the quantum resource to propose a MSQKD protocol, in which the classical participants do not need a Trojan horse detector and the TP is dishonest. Furthermore, the proposed protocol is shown to be secure against well-known attacks and the classical participants only need two quantum capabilities. Therefore, in comparison to the existing MSQKD protocols, the proposed protocol is better practical.