UMKESS: user-oriented multi-group key establishments using secret sharing

With the rapid development of group-oriented services, there are more and more multi-group communications in which users may join multiple group communications simultaneously. For example, in a wireless body area network (WBAN), medical personnels get together to hold a consultation for the patient and multiple consultation groups co-existed at the same time. A doctor may join more than one consultation groups simultaneously. Most existing group key establishment schemes establish a single group key for a single group. Applying a conventional group key establishment scheme in a straightforward manner (that is, running many times) can provide group-key-oriented multi-group key establishments. Since most group key establishment schemes suffer from larger rekeying overheads if users depart or join the network frequently, it is obvious that these schemes are not suitable for multiple groups co-existing applications such as WBAN. In this paper, we define a new type of user-oriented multi-group key establishments using secret sharing (UMKESS) for secure communications in WBAN. Since health data are private and sensitive information, efficient and secure data transmission in cloud-assisted WBANs is needed. In our proposed UMKESS, each user keeps only one share and uses the share to join multiple groups simultaneously, that is, or achieve multiple things at one stroke. Furthermore, the key generation center can manage user departing or joining dynamically with no rekeying overhead. The security strength of UMKESS is discussed in detail. In comparing to the latest group-key-oriented multi-group key establishment using secret sharing, UMKESS significantly improves the effectiveness of the multi-group communications and it is desirable for WBAN.