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Blockchain for IoT Security

Transaction Validation Rules: Blockchains have various transaction valida­

tion rules; however, most of these were developed to support financial trans­

actions. Generally, the IoT environment consists of heterogeneous devices

serving different operations and generating data in different formats with no

standardization. These can be challenging to transaction validation rules.

4.10  CURRENT BLOCKCHAIN APPLICATIONS FOR IoT

Scholars and researchers are continuously developing ways to improve blockchains

for IoT implementations. Blockchain’s advantages of decentralized architecture, trust

model, fault tolerance and smart contracts complement IoT’s security challenges.

Table 4.2 lists some of the blockchain-based applications developed to address the

limitations of IoT.

4.11  OPPORTUNITIES AHEAD

There are multiple areas where development is required to address the present-day

challenges of blockchain to empower it to address the requirements for IoT integra­

tion. Some of the critical areas for future developments are listed here:

IoT-based consensus protocol (Makhdoom et al. 2019): Generally, in the IoT

environment, the transactions are not related to the previous transactions.

One such case could be reading a sensor, where every reading is inde­

pendent of the values recorded previously. Thus, for these transactions to

be validated, we need a better and contextual to the IoT implementation

and environment. Another crucial area of improvement is minimizing the

latency of transaction validation.

Fault tolerance: IoT devices are also physically vulnerable, thus providing

opportunities for adversaries to introduce or corrupt existing devices into

malicious nodes. Thus, a consensus protocol must have the ability to sustain

and serve effectively despite malicious nodes in the ecosystem (Makhdoom

et al. 2019).

Blockchain size (Makhdoom et al. 2019): Blockchains were not developed to

run on resource-constrained systems like IoT. Multiple models have been

proposed to address this, such as an off-chain network of private nodes in

the form of a Distributed Hash Table (DHT) (Aniello et al. 2017), intro­

ducing universal and regional blockchains (“ADEPT: An IoT Practitioner

Perspective” 2015), sidechains (Zyskind et al. 2015a, b) and a distributed

database of transactions (Gaetani et al. 2017; Aniello et al. 2017).

Scalability: The miner nodes store the complete blockchain and validate the

transactions. This storage is one of the critical security features. However,

with the increase in transaction volume, this can be a bottleneck, resulting

in high latency.

Secure integration of IoT device and blockchain: Smart contracts play an

essential role in providing a secure way to integrate authorized IoT devices

in the blockchain platform.