Scalable Deniable Group Key Establishment
To simplify the design process for a group key establishment protocol, it can be convenient to restrict first to a scenario with a passive adversary, where the problem of authenticating protocol participants does not need to be addressed. The popular Katz-Yung compiler from CRYPTO 2003 can be used to transform unauthenticated group key establishment protocols into authenticated ones. In this paper, the authors present a modification of Katz and Yung's construction which maintains the round complexity of their compiler, but for 'Typical' unauthenticated group key establishments adds authentication in such a way that deniability is achieved as well. As an application, a deniable authenticated group key establishment with three rounds of communication can be constructed.