Table 1.

Comparison of consensus protocols.

Consensus Mechanism	Type of Blockchain Used	Advantages	Limitations
PoW	public, permissionless	high security, malicious node tolerant	not efficient, high energy consumption, high computation cost
PoS	public, permissionless	power efficient, high security	concept of “stake” is not applicable in IoT
PBFT	permissioned	high throughput, low computational overhead	susceptible to Sybil attacks, poor scalability