Two-party Mutual Authentication Quantum Key Agreement Protocol

Based on single-particle states and four-particle GHZ states, a mutual authentication quantum key agreement protocol is proposed. The quantum key agreement protocol can not only establish shared keys fairly, but also authenticate participants' identities before negotiating keys. In order to mutually authenticate each other's identity, the verifier can identify the identity of the prover according to whether the prover can choose the correct measurement bases with the hash values of their shared secret identity information and the random number. In key agreement stage, two parties can fairly establish a shared key by using the measurement correlation property of four-particle GHZ states. The shared key involves the partial keys of two participants, their identity information and the values of two random numbers. Although the hash functions are used in both the mutual authentication stage and the key agreement stage, the new quantum key agreement protocol is still proved to be unconditionally secure. Moreover, it has flexible qubit efficiency and can achieve high qubit efficiency.