Paper 2006/452

Hybrid Protocol For Password-based Key Exchange in Three-party Setting

TingMao Chang, Jin Zhou, YaJuan Zhang, YueFei Zhu

Abstract

Modular design is a common approach for dealing with complex tasks in modern cryptology. The critical of this approach is that designing a secure hybrid protocol. In this paper, we study password-based key exchange in the three-party setting within the UC framework and design a hybrid protocol that UC-securely realizes such task. That is, we firstly define an appropriate ideal functionality F3-pwKE for password-based three-party key exchange. Next we partition the task into two sub-tasks, three-party key distribution and password-based two-party key exchange, and propose relevant two ideal functionalities, F3-KD, FpwKE. Finally, we present a (F3-KD, FpwKE) -hybrid protocol for password-based three-party key exchange that is proved to be UC-secure with respect to non- adaptive party corruption.