When blockchains were first being built, they were envisioned as being able to provide a ‘one size fits all’ solution, meaning that all transactions, smart contracts, or anything else is performed on a single chain. However, it’s clear now that such a system isn’t so practical, especially when there are scalability limits and innovation constraints.
Cross-chaining is the interoperability between two relatively independent blockchains. The other words, it allows blockchains to speak to one another because they’re built in a standardized way. Cross-chain implementation is mainly represented by asset swap and asset transfer, which are both important part of the blockchain world and a key research direction of ECOCHAIN. With cross-chaining the limitations of a single chain can be avoided.
Cross-chain interaction can be divided into isomorphic cross-chains and heterogeneous cross-chains according to the different underlying technology. For isomorphic chains, the security mechanism, consensus algorithm, network topology, and block generation verification logic are consistent and the cross-chain interaction between them is relatively simple.
On the other hand, the cross-chain interaction of heterogeneous chains is relatively complex and involves different technology architectures such as the PoW algorithm of Bitcoin and PBFT consensus algorithm of Tendermint. The block composition and the deterministic guarantee mechanism are quite different, therefore a direct cross-chain interaction mechanism is not easy to design. Cross-chain interaction between heterogeneous chains generally requires third-party services.