The number of blockchain projects and the infrastructure built on them is increasing, which leads to the existence of many independent blockchains.



 This poses a problem for their interaction with each other, making it necessary to develop technologies for "communication" between blockchains. In this article, we will discuss some of the ways in which the problem of (in) compatibility of blockchains is being addressed.

One major step towards linking blockchains was the BTC Relay project of the ConsenSys and Ethereum teams, which allows interaction between the Bitcoin and Ethereum blockchains. Securely generating random numbers in Ethereum smart contracts is one of the most difficult tasks but can be made safer by using BTC Relay. Sidechains are another option, but they are not appropriate for all projects. Polkadot is an ambitious relay blockchain project that aims to provide security and coordination by having blockchains rent parachains validated by Polkadot miners.

Cosmos and Polkadot offer different benefits. Cosmos is more flexible in development and cheaper but has a limited number of projects compared to Polkadot. Polkadot maintains chain safety and offers simplified messaging between threads. Polkadot's Substrate software development kit also offers 3 consensus algorithms out of the box: GRANDPA, Rhododendron, and Aurand.

The Cosmos network allows each blockchain to use any consensus algorithm that complies with the ABCI specification, which standardizes communication between chains, but only Tendermint is currently compliant. Tendermint has the advantage of being asynchronous but its speed is inversely proportional to the number of transactions.

In Polkadot, only a limited number of chains can run on the relay chain, determined by an auction requiring a large number of DOT tokens. On the other hand, anyone can build a hub or zone on the Cosmos network, and hubs are sovereign blockchains that connect numerous other blockchains. This hub-and-zone model makes cross-chain communication more efficient because each blockchain only needs to connect to a hub instead of multiple other blockchains.

The Block Collider/Overline has not been mentioned in this article. Is the purpose of this article to provide a review? If so, that is acceptable. Moving forward, what are the plans for publications related to this topic?

It is important to note that there may be other developments and projects related to blockchain communication that have not been covered in this article. As the field of blockchain continues to evolve, it is crucial to stay updated on new technologies and advancements.

On the plus side, one of the biggest advantages of using blockchain for communication is transparency. All participants involved can see the same information, which reduces the chances for fraud or manipulation. This trustless environment is crucial, especially in industries where integrity is paramount.

Another significant advantage is the level of security it provides. Since data on the blockchain is encrypted and decentralized, it makes it really hard for hackers to target a single point of failure. The use of cryptography also helps in protecting sensitive information from unauthorized access.
Blockchain communication allows for peer-to-peer interactions without needing a central authority. This can result in faster transactions and less overhead costs. For example, in international money transfers, blockchain can eliminate the need for intermediaries, which can speed things up and make it cheaper.

However, there are some disadvantages too. One of the main issues is scalability. As more users join and transactions increase, the blockchain can become slower. This especially affects transaction speed during peak times, which can be a big drawback for real-time applications.

Another disadvantage is the complexity of the technology. Many businesses and individuals may struggle to understand how to implement blockchain communication effectively. This steeper learning curve can limit its adoption, especially for smaller companies who don't have the resources to invest in training or infrastructure.

Additionally, there are still regulatory uncertainties surrounding blockchain technology. Governments across the world are still figuring out how to regulate this tech. This can create uncertainty for businesses looking to implement blockchain communication, as they may be worried about future compliance issues.

Energy consumption is a concern too. Certain consensus mechanisms like Proof of Work require a lot of computational power, leading to higher energy costs and environmental impact. This is something that companies need to consider when deciding on incorporating blockchain into their communication systems.
While blockchain communication offers enhanced security, transparency, and efficiency, it also faces challenges like scalability issues, complexity, regulatory uncertainties, and energy consumption. As a programmer, it's crucial to weigh these factors when considering the integration of blockchain technology.