Improved quantum key agreement protocol with authentication

In order to make the quantum key agreement process immune to participant attacks, it is necessary to introduce the authentication in the communication process. A quantum key agreement protocol with identity authentication that exploits the measurement correlation of six-particle entangled states is proposed. In contrast to some recently proposed quantum key agreement protocols with authentication, this protocol requires neither a semi-trusted third party nor additional private keys in the authentication process. The entire process of authentication and key agreement can be achieved using only n six-particle entangled states, which saves communication costs and reduces the complexity of the authentication process. Finally, security analysis shows that this scheme is resistant to some important attacks.