Self-Healing Group Key Distribution with Extended Revocation Capability

Self-healing group key distribution schemes (SH-GKDS) allow large and dynamic groups of users to establish group keys over an unreliable broadcast channel for secure multicast communications. In most existing schemes, total number of users that can be revoked during system lifetime is bounded by the degree of applied polynomials. In this paper we present a new revocation mechanism which overcomes this limitation. It allows to revoke a predefined number of users in each session, regardless of the number of users already revoked in the past sessions. To illustrate our approach, we propose SH-GKDS scheme with extended revocation capability which applies our revocation mechanism. Then, we conduct security and performance analyses of the scheme to show, that the proposed construction is efficient, achieves forward and backward secrecy, and resists collusion between the newly joined users and the revoked users.