Everyone said that 2019 is the year public blockchains took off, and 2020 will be the first year blockchain began to achieve business adoption. Although the coronavirus pandemic continues to wreak havoc on all walks of life worldwide, the blockchain industry is making great strides forward.
In just a few years, the blockchain sector has developed from 1.0 to 3.0, and each upgrade has brought about some changes in the world. As we all know, blockchain 1.0 generally refers to cryptocurrency centered around Bitcoin. Blockchain 2.0 is public chains represented by Ethereum, which can develop smart contracts. In the era of blockchain 3.0, people think that thousands of blockchains can coexist and interoperate.
In the past two years, people have had high expectations of many public chains. However, some of the so-called “blockchain 3.0” projects have either shown slow progress or failed to live up to the expectations after their mainnet went live. People then began to expect to see a killer DApp achieving wide adoption of blockchain. At the same time, as the underlying technology for blockchain connectivity, multi-chain structure and cross-chain technology have become an important part of ‘blockchain 3.0’.
aelf and other Web 3.0 projects can be seen as the underlying technology providers for the Internet of Value. On the aelf blockchain, whether it is valuable information or digital currency, everything can be connected and shared, which is where the magic of cross-chain technology lies.
If the consensus mechanism is the core competitiveness of blockchain, then the cross-chain technology is the key to realizing the Internet of Value for blockchain, particularly for alliance chains and private chains. It is the key to preventing different blockchains from being isolated islands and serves as a bridge connecting blockchain and the outside world.
Cross-chain technology is designed to prevent blockchain from being isolated islands of data
At present, although these public chain projects have seen their performance improved, none of them is able to build the much-anticipated “underlying blockchain highway’ singlehandedly. In particular, driven by the prevailing view that each public chain should be an independent ecosystem, public chains today have become isolated islands of data with different architectures incompatible systems, which poses real difficulty to DApp developers.
The cross-chain technology, as the name suggests, is aimed to realize asset circulation, information exchange and application collaboration between different blockchain platforms. It can be likened to a bridge linking different public chains, which can help realize data transmission between different blockchain networks and greatly reduce transmission costs.
It is obvious that the demand for cross-chain technology is very urgent in today’s blockchain world.
Cross-chain communication can be divided into homogeneous and heterogeneous cross-chain according to different underlying blockchain technology platforms. Cross-chain interaction between homogeneous chains is simple, since their security mechanisms, consensus algorithms, network topology, block generation verification logic are consistent. Cross-chain interaction between heterogeneous chains is quite different. For example, Bitcoin uses PoW algorithm while the alliance chain Fabric uses traditional deterministic consensus algorithm, and its block form and deterministic guarantee mechanism are very different. Since designing a direct cross-chain communication mechanism is not easy, cross-chain interaction between heterogeneous chains generally requires third-party services.
aelf is doubling down on heterogeneous cross-chain research
At present, cross-chain technology mainly includes notary schemes, hash-locking, side chains or relays, and distributed private key control. aelf uses the side chain or relay scheme.
aelf’s cross-chain logic is ‘main chain + side chain’, with an emphasis on ‘one chain, one scenario’, where each side chain can be a scenario, such as a DApp, or a DeFi app. aelf’s cross-chain architecture is centered around the main chain.
In the cross-chain process, aelf achieves intercommunication between different chains via indexing. An index is the transfer of data from one chain to another in a defined structure. The cross-chain index has two steps: parent chain indexing child chain and child chain indexing parent chain.
- The parent chain requests data from the child-chain and the data are then sent from the child chain to the parent chain.
- The parent chain processes all the child chain’s index data, generating a Merkle tree, and stores it on the chain. The child chain block has been indexed by the parent chain, and must wait for the data to be confirmed by the network.
The above steps include the whole process of the parent chain indexing the child chain’s block and the child chain re-indexing the parent chain’s block. It’s worth noting that only irreversible blocks can be indexed by other chains.
As a result, aelf does not need a Hub or a relay chain and is more of a decentralized cross-chain model. This is because communication between different chains does not necessarily require the permission of the aelf’s only main chain each time. The multi-layer child chains under the side chain can also communicate with each other with the index of the upper-layer parent chain and without the main chain getting involved.
On the premise of decentralization, aelf established that only confirmed blocks can be indexed, because only irreversible data can be trusted to ensure the network’s security. aelf also has its own solution for communicating with the Ethereum ecosystem, which can be interfaced with the Ethereum and other blockchain systems via adapters, making it compatible with existing mainstream ecosystems.
It can be seen that aelf has done a great job in homogeneous cross-chain technology, whereas some public chain projects have yet to pull it off. aelf has also begun to develop heterogeneous cross-chain technology, which will allow external chains such as Bitcoin and Ethereum to lock tokens into smart contracts and generate ccorresponding tokens on the aelf chain through contracts to achieve cross-chain communication. It is clear that aelf has taken the lead in cross-chain development.
While it’s still too early to talk about blockchain 3.0 and most projects are still trying to figure out where the underlying technologies are heading, solving the scalability issue public chains are facing today through the cross-chain technology has become the general trend. Cross-chain technology can realize communication between different chains, greatly improve blockchain’s ability to transfer value, and promote the development of IoT and cloud computing. On the other hand, without cross-chain technology, all kinds of blockchain platforms information will just be isolated islands of data, putting a significant limit on the applications of blockchain platforms.
We believe that the cross-chain mechanisms will greatly increase the value of blockchain and usher in a new era of blockchain development. With strong technical prowess and the ability to achieve commercial application, aelf will continue to explore the cross chain technology and provide strong technical support for the rapid and steady development of the industry!
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