Original author:Nicole Cheng(Analyst of OFR)
Advisor: JX (Partner of OFR)
Original source: Mirror
Original author:
Original source: Mirror
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With the outbreak of the multi-chain ecology, the TVL of the cross-chain protocol bridging the ether has also shown a rising state in the past six months. However, due to different communication protocols, identity management, consensus mechanisms and other differences between different blockchain systems, cross-chain interoperability still faces problems similar to the classic impossible triangle - namely, scalability, security and decentralization degree of transformation. The following will measure the cross-chain bridges currently on the market based on these three dimensions, and discuss the development space and possibility of cross-chain bridges in the future.
Before discussing the different dimensions of the cross-chain bridge, let's first look at the working steps and principles of the cross-chain bridge. Assets are successfully transferred from the source chain to the target chain, usually through the following steps:
Status monitoring: Monitor the status on the source chain through oracles, verifiers or repeaters, and obtain cross-chain requests in a timely manner.
Information transfer: Once a cross-chain request is received, the information is transferred from the source chain to another chain (intermediate consensus chain or target chain).
Reaching a consensus: After the participating nodes of the monitoring chain reach a consensus, the information is further transmitted to the target chain.
Cross-chain is completed by locking native assets, minting and destroying mapped assets. When crossing from chain A to chain B, the assets on chain A are locked in its smart contract address by the cross-chain protocol, and the smart contract on chain B is notified through the oracle to cast an equivalent amount of mapped assets on chain B. When the user needs to cross back to the A chain, the mapped assets on the B chain will be destroyed through the smart contract to redeem the original assets on the A chain.
safety
Aggregate liquidity through mining incentives, establish and use liquidity pools in A and B chains as cross-chain asset reserves, and use locking and dispute mechanisms to ensure that participating nodes cannot transfer user assets.
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There are corresponding risks in the two cross-chain bridge working modes mentioned above. The first type of bridge involves the risk of over-issue and the risk of malicious nodes. Since data information such as cross-chain requests, native token locking, and mapped token casting are provided by third-party verification nodes, the security of users or liquidity provider funds is highly dependent on the accuracy of these validators, not the source chain or target chain security. The cost and cost of a validator breaking security depends on the assets it pledges. The cross-chain protocol should ensure that the mortgage assets are always greater than the verification amount to prevent the risk of evil.
decentralized
The second cross-chain scheme of liquidity network, because the assets used by users in the B-chain are not the mapped tokens minted by the cross-chain bridge, but the universal tokens that deploy native token smart contracts on the B-chain, Therefore, the assets after the cross-chain have been separated from the endorsement support of the cross-chain bridge. This kind of non-custodial solution, because the possibility of universal token crash is less than that of mapping token, the security has been greatly improved compared with before. However, it is still highly dependent on the intermediate consensus layer. Once the degree of decentralization of the consensus layer is insufficient, assets are still at risk of being stolen. Therefore, the network needs to contain as many nodes as possible, and at the same time set reasonable economic incentives to prevent node operators from doing evil, so as to ensure maximum security.
The most direct criterion for judging the degree of decentralization is the number of nodes participating in the verification. The greater the number, the more difficult it is for nodes to do evil collectively, and the correspondingly the higher the degree of decentralization. The following table lists the common cross-chain bridges currently on the market, the number of assets and blockchains they support, and the number of nodes.
scalability
It can be seen from the above table that ThorChain currently has the largest number of nodes, followed by Anyswap and Connext. However, ThorChain does not disclose the specific information of its node operators, and the reliability of anonymous operators is doubtful. Under the highest degree of decentralization, there is still a question mark over its security.
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The scalability is divided into the scalability of the asset pool and the scalability of the transaction. The scalability of the transaction is subject to the block generation speed and security of the source chain and the target chain, while the scalability of the asset pool depends on the liquidity incentive or the total number of pledged assets.
The scalability of the asset pool is only applicable to the second liquidity pool model mentioned above, and sufficient incentives are needed to ensure that the liquidity is always sufficient. However, although the security has been improved compared with the first mode, its architecture level is also more complex, and the increase in deployment difficulty means that more development time is required, which will also lead to reduced scalability.
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1. Cross-chain NFT bridge
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2. Omnichain dApps (odApps) concept bridge
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3. Cross-chain aggregator
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4. Cross-chain communication facilities
5. Layer 2 cross-chain bridge
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References
Multichain dapp guide, standards, and best practices
Blockchain Bridges: Building Networks of Cryptonetworks
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