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interaction of more than one smart device. The parachain can have its own set of

validators and also its own cryptocurrency. It should be noted that Parachains can’t

implement their own consensus model and would require reserving a slot in the Relay

Chain via auction using DOT.

III.

Using Bridges

Under certain extreme cases, it may be necessary to implement a separate blockchain,

which is technically unique. It may also be so that a certain group of smart devices,

which is already running on blockchain, wants to be a part of the larger ecosystem.

In such cases using Parachain may not fulfill the requirement. Under these circum-

stances, bridges are to be used. If the blockchain supports smart contracts that Bridge

Contracts can be used for easier implementation. Otherwise, separate Bride Modules

can be designed using substrate to achieve the goal of interoperability. However, it

should be noted that Bridges can’t directly connect to a slot in Relay Chain and must

connect via a Parachain or a Parathread.

IV.

Support of Smart Contract

Substrate is the framework that is used to build polkadot, and this can be used to build

other blockchains, which can interact with the Polkadot Relay Chain by any of the

previous discussed methods. Substrate enables us to create blockchains, which can

or cannot support smart contracts. Support of smart contract plays an important role

when using blockchain for IoT and more evidently when frameworks like Substrate

are used.

Supporting smart contract has the following pros when considered with respect

to IoT:

1.

Implement condition-based decision-making on-chain.

2.

Enable future applications to be built on the blockchain.

3.

Create a defi-based model coupled with the IoT implementation.

However, integrating smart contracts also has some cons associated with it:

1.

The node requires more resources and most IoT projects have limited resources.

2.

Smart contracts are a source of vulnerability where anyone can exploit a bug in

any smart contract for personal benefits.

While creating the side chain, the above points must be considered. Since most

IoT projects are inclined towards faster transactions, smart contracts can be an added

overhead with limited benefits.

4.3

Survey of Contemporary Interoperability Engines

and Platforms

When it comes to interoperability and cross-chain transaction, Polkadot is not the

only one in the race. At a base level, using Oracles can help achieve some of the