Invitation-Oriented TGDH: Key Management for Dynamic Groups in an Asynchronous Communication Model

In this paper, we propose a suite of group key management protocols that allows a group of users to agree on a shared group key, which can be used to protect a shared file system stored remotely in the cloud. Our protocols support the refreshment of the group key at each group membership modification. Compared to other similar solutions, the key novelty of our protocols is that they require asynchronous communication channels, and only constant number of exponentiations on average, worst case logarithmic number of exponentiations even if membership modifications are controlled by arbitrary user. Moreover, our scheme is fully decentralized, and its design is led by a practical, invitation-oriented approach.