A Time Constraint Three-Party Encrypted Key Exchange Protocol

We propose a time constraint three-party encrypted key exchange protocol in which both two parties/clients only act as the roles within the relationship of exchanging secure messages constrained by the intersection time periods. The technique of time constraint, in this paper, is that a trusted server generates a serial of secure exchanging messages, which are used to generate multiple session keys by each party individually. Each session key corresponding to one time period which is belonging to the intersection set from both two parties' requesting time bounds. Only both two authorized parties/clients can communicate to each other within the intersection set of time bounds. It can get better performance on when three parties do many times for traditional 3PEKE protocol. Our approach can improve the performance of traditional 3PEKE scheme via the technique of time constraint. Furthermore, we proof the scheme can also against the password guessing attack as well as replay attack.