HLOChain: A Hierarchical Blockchain Framework with Lightweight Consensus and Optimized Storage for IoT

Table 1

Some major notations used in this paper.

Notations	Description
	The i-th node
	The identity of
	The role level identifier of , where , and represent high-level, mid-level, and low-level nodes, respectively
	The public and private key pair of
	The block height
	The hash of previous block (the last validated block)
	The number of candidate nodes in the current consensus iteration
	Random value
	The maximum number of candidate nodes that the network load can tolerate
	A signature algorithm
	The i-th block
	The i-th block header
	The state body of i-th block
	The transaction body of i-th block
	The version number of account j