[Retracted] HGKM: An Efficient Hybrid Group Key Management for Unmanned Autonomous Vehicles MBN in Wireless Network Environment

Table 5

The join operation’s calculation cost for TKC.

Group key management	Cost of joining an action for TKC calculation
	Leader unit	Member unit
HGKM
LKH
OFT	2

: he tallest of the key tree for operation unit in HGKM. h: the highest of the group key tree in LKH and OFT.