A secure authenticated semi-quantum key distribution scheme for semi-quantum environments

Abstract

One of the notable applications of quantum computing is in cryptography. However, quantum apparatus is still costly at this time. In practicality, some users may not have full quantum capabilities. Boyer et al. in 2007 proffered a semi-quantum key distribution scheme, in which one participant is a quantum user, and the other participant is a classical user. The classical user has limited quantum capabilities. In 2021, Chang et al. proffered an authenticated semi-quantum key distribution (ASQKD) scheme. However, in the Chang et al. scheme, an authenticated classical channel is assumed to be pre-established between a quantum user and a classical user. Once the authenticated classical channel is not available in communication environments, the scheme will be vulnerable to attacks. An ASQKD scheme without authenticated classical channel is more sutable for semi-quantum environments. Therefore, we propose a more secure authenticated semi-quantum key distribution scheme without authenticated classical channel for semi-quantum environments. Our scheme only uses single photons to achieve proven security. In our scheme, the semi-quantum environment contains a quantum user and a classical user. The provable security analysis of our scheme is provided. Our scheme can withstand reflecting attacks and impersonation attacks. We also show the proposed scheme can provide the robustness against collective attacks. That is to say, when there is a collective attack on our scheme, any unitary operator from the attacker to acquire useful information will be detected. Moreover, we also do the performance evaluation and comparison with other relevant schemes. The results show that our scheme has the following preferable properties: high qubit efficiency, no quantum memory (storage) required, no classical channel required, and secret Hash function for the session key. Therefore, our proposed scheme in semi-quantum environments is a secure scheme.