Measurement device–independent quantum secure direct communication with user authentication

Quantum secure direct communication (QSDC) and deterministic secure quantum communication (DSQC) are two important branches of quantum cryptography, where one can transmit a secret message securely without encrypting it by a prior key. In the practical scenario, an adversary can apply detector-side-channel attacks to get some non-negligible amount of information about the secret message. Measurement device–independent (MDI) quantum protocols can remove this kind of detector-side-channel attacks, by introducing an untrusted third party, who performs all the measurements during the protocol with imperfect measurement devices. In this paper, we put forward the first MDI-QSDC protocol with user identity authentication, where both the sender and the receiver first check the authenticity of the other party and then exchange the secret message. Then, we extend this to an MDI quantum dialogue protocol, where both the parties can send their respective secret messages after verifying the identity of the other party. Along with this, we also report the first MDI-DSQC protocol with user identity authentication. Theoretical analyses prove the security of our proposed protocols against common attacks.