Table 2.

Technical aspects of blockchain and smart contracts’ methodologies for technical CCAM challenges.

Ref	Challenge	Blockchain/ Smart Contract	Consensus Mechanism	Techniques/Tools	Performance of the Methodology
[44]	Security	Blockchain	PoW and PBFT	-	Better performance in computation and transmission times as the number of verification signatures increases, compared to existing solutions (IBV, SPRING, IBCPPA, and EAAP)
[45]	Security	Blockchain	PoW	-	It implements the BIP325 key extraction algorithm to avoid preloading keys and burdening OBUs with storage consumption. The performance of the technique is not affected by the average speed as far as packet loss is concerned
[46]	Security	Permissionless Blockchain and Smart Contracts (Ethereum)	PoW & PoS	-	The methodology is efficient for small delay time in the transmission of messages from the group of “good” nodes
[47]	Privacy	Blockchain	PoW	Distributed Cloud Servers	It achieves fewer cycles (steps) in communication compared to pre-existing methodologies
[48]	Decentralization	Blockchain	PoQF	Game Theory, VEC network	Compared to the rest of the consensus mechanisms studied, it has less loss when validating events, but this has the impact of the longest delay in message transmission
[49]	Sensing Accuracy	Permissioned Blockchain and Smart Contracts	DPoS	DNNs	Position correction compared to other methodologies is more effective when we have many errors from the sensors
[50]	Audit	Blockchain	PoS	-	Moderate transmission speed performance—High security