Blockchain in IoT and Beyond: Case Studies …

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needed interoperability but those are neither easy to implement nor easily scalable.

Some other blockchain technologies that also aim at interoperability are Blocknet,

Aion Online, Wanchain, Cosmos Blockchain.

Among all the mentioned projects, Cosmos Blockchain is one of the popular

options [33]. Blockchain networks built using prebuild and/or custom modules using

the Cosmos SDK can interact with other Cosmos Blockchain via IBC to Cosmos

Hub. IBCor Inter-Blockchain Communication Protocol is an end-to-end, connection-

oriented communication protocol designed for interaction between heterogeneous

blockchain networks. Using IBC, a wide range of Dapps can be built, which can

facilitate tasks like cross-chain token transfer and atomic swaps. Presently, IBC is

implemented using Cosmos SDK.

5

Open Challenges and Discussions

Although integrating blockchain with IoT unlocks new potentials, they are still

subjected to certain challenges [34]. This section discusses two of such challenges,

which have seen enormous amounts of research work in recent years but still have

not been perfectly addressed.

I.

Transaction Speed: The throughput of the blockchain network, which is

measured by the number of transactions per second, can act as a bottleneck

in case of IoT. Most IoT solutions require fast decision-making and record-

keeping, which demands high throughput. To achieve this, such a consensus

mechanism should be introduced, which can promise high throughput without

compromising security. Consensus algorithms have been proposed that “solve”

this problem but each of these has its own disadvantages. For instance, Byzan-

tine Fault Tolerance derivative algorithms have high asymptotic complexity,

Proof of Stake, which was proposed as an alternative to Proof of Work intro-

duces centralization in the system in form of prejudicial “stake” in the whole

network asset, Kafka has also been tested out in Hyperledger Fabric and has seen

criticism because it introduces a single point of failure in the network during

consensus.Assuchabalancebetweentransactionspeedandtheaforementioned

handicapping factors does not exist in literature at the time of writing.

II.

Running Nodes: A blockchain network comprises multiple nodes, which are

responsible for validating transactions and adding new blocks. In most cases,

validating a transaction includes solving a cryptographic puzzle, which requires

computing power. How the network rewards this computing power is decided

by the consensus mechanism, however, the network is dependent on computers,

which can solve these puzzles. This makes blockchain network resource-

intensive, which makes it challenging to implement it cost-effectively and scal-

ably in IIoT solutions. However, there are works in literature, which show a