A novel batch-based LKH tree balanced algorithm for group key management

Logical key hierarchy (LKH) is the most suitable key management scheme for a large dynamic group [1, 2]. Ref. [3] proposed LKH key management scheme, but it did not discuss how to keep tree balanced when membership changes. Ref. [4] proposed LTM (LKH Tree Manager) algorithm, but it has high relocating cost. Ref. [5] proposed a tree balanced algorithm, but had not given out detailed steps. Ref. [6] proposed batch balanced algorithm (BBA), but it causes high cost for reconstructing the tree. In this paper, we propose three merging algorithms and a novel tree balanced algorithm.