- The significance of cross-chain lies not only in the increase of blockchain scalability, but also in the means to achieve interoperability between different blockchains.
- There are three main methods of cross-chain implementation: notary mechanism, side chain/relay, and hash lock. At present, the most mainstream cross-chain solution is the relay chain approach used by Polkadot.
- Until there is a breakthrough in cross-chain technology, Polkadot will still be one of the most high-quality public chains in the cross-chain market.
I. Overview of cross-chain solution development
The official launch of Ethernet in 2014 marked a new milestone in the development of public chains with the use of smart contracts, and various types of decentralized applications (DApps) could be built on the underlying public chains. At the same time, the industry is stuck in the “impossible triangle” problem, which has inspired various attempts in the industry to improve the problem. Among them, cross-chain is currently the most popular and widely used solution.
Note: “Impossible triangle” refers to the fact that blockchain can only satisfy at most two of the three aspects of decentralization, scalability and security, and the enhancement of one aspect means the sacrifice of the other.
Since 2016, the industry has been experimenting with cross-chain, which is not only a solution to the “impossible triangle” problem, but also a way to realize asset swap and value transfer in different blockchains. The early forms of cross-chain are Atomic Swap and the notary mechanism proposed by Ripple, a payment project, to improve transaction speed and interconnect different ledgers, Layer-2 construction and side chain expansion represented by BTC Relay are also ways to achieve cross-chain.
From the early stage of meeting the expansion of blockchain and improving transaction efficiency, to the emergence of Cosmos, Polkadot and other projects dedicated to connecting different blockchains and realizing cross-chain ecology, both in terms of technology and scenario application, they have experienced more diversified development. From the perspective of industry development, cross-chain has transformative significance.
In general, the cross-chain solutions launched by the industry can be mainly divided into four types: hash locking, notary mechanism, side chain and relay mechanism. Details of each scheme are shown in the following table.
Among the above cross-chain solutions, hash locking mechanism is simple and has limited functions, so it cannot support cross-chain asset transfer and cross-chain smart contracts; notary mechanism has the problem of centralization risk due to the reliance on notary nodes. As an upgraded version of the sidechain anchoring scheme, the relay mechanism is more superior in practical use, and Cosmos and Polkadot have gradually built a comprehensive and good ecological network while being sought after by the market.
Two, the mature relay cross-chain solution: Cosmos and Polkadot
Cosmos was officially launched on the main website in March 2019. Its goal is to create a network between blockchains, breaking barriers and building bridges to realize cross-chain transactions and interactions between blockchains while maintaining the sovereignty of each chain (Sovereignty).
Cosmos has three technically important parts: Tendermint, Cosmos SDK and IBC. tendermint is the consensus engine and BFT consensus algorithm. In simple terms, Tendermint ensures that transactions are recorded in the same order on different machines, and supports processing transactions in any computer language, saving the time required for development. IBC is an inter-blockchain communication protocol that enables connections between different blockchains (Zones in Cosmos).
Cosmos Hub is the first Zone in the Cosmos network and is essentially a multi-asset distributed ledger designed to connect Zones. The native pass, Atom, is the only collateral pass on Cosmos Hub, giving the holder the right to vote, verify and delegate verification, but the transaction fee can be paid by any pass. atom uses an inflation mechanism, with 1/3 of the total number of atoms being issued each year; at the same time, the initial number of verifiers will be set at only about 100 to maintain the speed of transactions.
In the Cosmos ecosystem, there are already applications such as Hard, Kava, Iris and so on. At present, the market capitalization and the number of users of DApps developed based on Cosmos public chain are still much smaller than Ether and Polkadot, indicating that the development of Cosmos is somewhat stagnant. However, public chains that use Cosmos SDK as the underlying development framework include Binance Chain, Terra and Lino, indicating that Cosmos sdk is one of the most popular blockchain development frameworks currently.
The three important players in the Polkadot mechanism are Relay Chain, Parachain and Bridge, which, by analogy with Cosmos, correspond to the concepts of Cosmos Hub, Zone and IBC in Cosmos. Parallel chains can access the Polkadot network permanently or transiently in the form of Parathreads; bridges enable the exchange of connections between parallel chains and external blockchain networks such as Bitcoin and Ether.
The role design in the Polkadot consensus mechanism is more complex, consisting of a Validator, Nominator, Collator, and Fisherman. The checker provides proof for the validator while the fisherman is responsible for monitoring the network for malicious behavior of the validator.
The design of the Polkadot consensus mechanism role has the significance of better securing the network. Since the roles of parallel and relay chains in Polkadot network are similar to those of child and parent chains, i.e., the security of parallel chains is guaranteed by the relay chains, and the relay chains have the theoretical final say on the state change of parallel chains. Therefore, it is especially important to ensure the security of the relay chain.
Currently, there are three networks in the Polka ecosystem, Polkadot, Kusama and Recoco, among which, Recoco is a relay chain testing network, which can test the consensus mechanism on parallel chains and the interaction between parallel chains, and only the tested parallel chains can participate in the slot auction. Kusama is an early beta version of the Polkadot network, with similar code but independent of each other, Kusama has faster governance and a lower entry barrier than Polkadot. Parallel chains are tested by Kusama before they are deployed on the Polkadot network. This not only helps project owners to test their projects or experiment and innovate, but also ensures the security and stability of the Polkadot network.
According to Polkaproject’s official website, there are 459 projects running on Polkadot and 149 projects built with the Substrate platform. The ten most active projects in the ecosystem are: Polkadot, Phala Networ, Toystream, ChainX, Reef Finance, PolkaBTC, Ocean Protocol, Crust Network, Darwinia, Centrifuge.
According to Polkadot’s official disclosure, the first slot of Kusama will be officially opened for auction (slot auction) on June 15, 2021 at 12:00 GMT. Each auction will last for one week, divided into a two-day bidding period and a five-day closing period. The current round of five auctions will take five weeks, followed by a break period before the next round of auctions.
Polkadot relay cross-chain solution, source: Polkadot, tokeninsight.com
The “New Player”: DOM Chain
The success of Cosmos and Polkadot has attracted more developers to get involved in cross-chain solutions, and many of them are imitators of both and try to make some improvements in their imitation. DOM Chain is one of the imitators.
DOM Chain is designed to mimic the BTY (Bitcoin public chain), which was released in early 2014, initially as a PoW version, and then switched to PoS in the second half of 2014, Bitcoin is the first public chain network to implement parallel public chain technology. The cloud chain corresponds to the parallel chains in the Bit$ network. The cross-chaining of public chains such as ethereum is in the form of a transit bridge, and the cross-chaining of bitcoin is in the form of a hash lock. Based on the DOM master chain, developers can scale multiple parallel cloud public chains simultaneously, and each cloud public chain can develop independent Dapp applications. Since the project ecosystem is still in the development stage, DOM-based DApps are still under development.
Unlike Cosmos and Polkadot, the Dom Chain mainnet uses the SPoS (Safe PoS) consensus algorithm. SafePoS is more decentralized, and the bookkeeping is done among 9 nodes, so it is more efficient than PoW and PoS algorithms. Unlike other public chains that use asymmetric encryption systems, DOM uses proxy re-encryption to encrypt information. In short, the cipher text encrypted by our public key can be decrypted only by our private key, and then transformed to be decrypted by the other party’s private key.
In terms of data structure, traditional public chains such as Ethernet use Merkle Tree or Merkle Patrcia Tree to store transaction data within the block, while Dom uses MVCCKVDB (Multi-Version Concurrent Control Database) to speed up data reading and writing, so that the blockchain can carry the transaction capacity has been improved.
DOM system architecture, source: DOM, tokeninsight.com
Compared with other mature cross-chain projects, DOM is still in the early stage of test network operation from the perspective of circulating market capitalization, and no project or demo has been deployed on this public chain. Due to the lack of ecology, the market capitalization in circulation on its test network is only about 5% of Cosmos, which is still a long way from the actual application and its user community is still in the process of construction.
Overall, since there is no breakthrough in cross-chain technology in the market today, the Polkadot solution is still the mainstream of cross-chain public chain development, while other cross-chain solutions are more compatible and imitation solutions based on Polkadot and Cosmos solutions. More developers tend to develop DApps for cross-chain public chains, i.e. parallel chain development, thus creating the hot Polkadot slot auction market. However, the diversity of the ethereum ecosystem and its strong liquidity make many users not yet accustomed to cross-chain asset interaction, and the demand for cross-chain is not yet too great.
However, with the growing number of users of Defi. Together with the auction of parallel slots, there will be more cross-chain applications accessing Polkadot mainnet. Until there is a breakthrough in cross-chain technology, Polkadot will still be one of the most high-quality public chains in the cross-chain market.
Posted by:CoinYuppie，Reprinted with attribution to:https://coinyuppie.com/the-new-player-in-cross-chain-projects-dom-chain/
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