Secure and efficient key distribution for collaborative applications

Confidentiality is a key demand for many collaborative applications in the Internet, e.g. business meetings. In a more and more mobile society there is an increasing need of spontaneous meetings in ad hoc environments, often with changing partners. To assure confidentiality of such meetings the partners have to agree upon a common secret key for encrypting their communication. While centralized collaborative systems provide practicable solutions for this, it still represents a challenging task in decentralized systems using the peer-to-peer paradigm. In this paper we present a simple key distribution protocol, called VTKD, which was especially designed for small dynamic peer groups. It consists of two parts: a mutual authentication of the partners and a secure key renewal. The protocol uses a virtual token to determine the partner responsible for the key generation and distribution procedure. VTKD fulfills the relevant demands concerning group key exchange and is more efficient related to key renewal delay than existing key exchange protocols