A Secure and Efficient Distributed Batch Rekeying Protocol for Dynamic Collaborative Groups

The traditional distributed individual rekeying protocols are inefficient and have high rekeying cost, while batch rekeying protocols are vulnerable to collusions attack. Aiming at those drawbacks, three algorithms are presented: 1) MST algorithm, which is used to merge two subtrees; 2) CARR algorithm, which is resistant to collusions attack, and can avoid a renewed node to be rekeyed more than once; 3) CST algorithm, which creates a subtree consisting of joining members and computes all the keys of the subtree during the rekeying period. Based on above algorithms, a protocol named SEDBR is proposed. Mathematical models of communication cost and computation cost are established by theoretical analysis, and the performance of SEDBR protocol is validated by simulation experiment. Analysis results show that SEDBR is a secure and efficient batch rekeying protocol, which is suitable for large dynamic collaborative group.