When security accidents occur frequently, the safety of the cross-chain bridge becomes a key factor for users to choose which “cross-chain protocol”.
Original title: “Is the cross-chain bridge you use safe?” An overview of the security protection and subtle design of Wanchain’s cross-chain mechanism
Written by: Ye Wei
Recently, there have been many security incidents related to “cross-chain” in the blockchain industry. Before that, cross-chain attacks had hardly been “cared for” by hackers. Perhaps the second half of 2021 will be the first year of cross-chain offensive and defensive warfare; and the safety of cross-chain bridges will become the most critical factor for users to choose which “cross-chain protocol”.
Through a short article, we will give you an overview of Wanchain’s cross-chain mechanism’s security protection, economic incentives, and other subtle designs.
Wanchain started the innovation and research and development of the cross-chain mechanism as early as 2017. In June 2018, it integrated the first public chain Ethereum in a decentralized way. After several iterations of versions, Wanchain launched the latest version of the cross-chain mechanism in February 2021, named the “Pledged Deposit Sharing Multi-chain Inter-crossing” mechanism, referred to as the “Multi-chain Inter-crossing” mechanism. Currently, Wanchain has integrated public chains such as Ethereum, Bitcoin, EOS, BSC, XRP, Litecoin, etc. across chains, and several other public chains such as Polkadot will also be launched in the near future. Stay tuned.
The characteristics of Wanchain’s “multi-chain inter-crossing” mechanism are as follows:
Cross-chain nodes run monthly, and the one with the highest amount of pledge wins
Currently, the Storeman Group on Wanchain consists of 25 Storeman, including one Foundation node.
From the 1st to the 7th of each month is the Storeman campaign period. According to the sum of the WAN pledge of the cross-chain node and the WAN entrusted amount attracted by the node, the top 25 nodes are selected from high to low to enter a new round of Storeman. Group. The WAN pledged by Storeman is used as the collateral for cross-chain assets, ensuring that in case of systemic risks (of course, with the current design of the “multi-chain inter-crossing” mechanism, the probability of such risks is close to zero), debts can be repaid with assets. At the same time, nodes and delegators that provide pledge deposits can receive daily pledge rewards, which greatly enhances the staking enthusiasm of nodes and delegators.
In addition, the monthly election mechanism makes the list of nodes no longer solidified, fresh blood will continue to come in, and old nodes will withdraw.
Distributed key control based on secure multi-party computing
The key control method of Wanchain’s “multi-chain inter-crossing” mechanism is distributed key control, and its core is Secure Multi-Party Computing (sMPC). The highlights are as follows:
Security: Wanchain has improved the key generation process and signature process of the existing threshold signature scheme (TSS), and combined with other cryptographic techniques to form a hierarchical threshold signature algorithm (H-TSS) and an aggregate threshold signature algorithm ( A-TSS), realizes more delicate management control authority for cross-chain locked assets, and improves account security by at least two orders of magnitude;
Degree of decentralization: Through the analysis of the algorithm principle, Wanchain proposed an original ECDSA threshold optimal signature algorithm (currently, it needs to be signed by at least 17 of the 25 nodes of Storeman Group at the same time), and each node obtains the basis through the preprocessing process Calculate the data and apply it to the multi-party calculation and multiplication operation of the signature process, and finally realize the property of the optimal threshold;
Computing and communication efficiency: By merging and reorganizing the process of multi-party security computing, the number of interactions between nodes is reduced, and the communication efficiency is improved; at the same time, in the ECDSA threshold optimal signature calculation, homomorphism is only used in the preprocessing process Encryption, and the signature process does not rely on homomorphic encryption, which greatly improves computational efficiency.
A cross-chain node group manages all bridges, and the node pledge deposit is shared by multiple chains
In terms of improving cross-chain security, efficient use of resources, and optimizing user experience, Wanchain’s “multi-chain inter-crossing” mechanism has greatly improved the cross-chain security and scalability. In the multi-chain crossover mechanism, all wanBridges are operated by the same Storeman Group and share the same deposit pool. This design reduces the complexity of cross-chain operations, improves the convenience of cross-chain, and enables cross-chain assets to circulate freely on each chain; at the same time, under the premise of ensuring the safety of cross-chain funds, the single bridge is greatly improved. The largest cross-chain quota.
The chain is directly connected, without using Wanchain as a relay
In the latest “multi-chain inter-crossing” mechanism, the Wanchain team successfully implemented the cross-chain mechanism of the “direct connection bridge” model. The so-called direct bridge means that the transfer of assets between two public chains can directly realize the cross-chain transfer of assets without passing through the Wanchain, which plays the role of routing. Take BTC from the Bitcoin network to Ethereum as an example:
When a user initiates a BTC cross-chain transaction, the Bitcoin-Ethereum cross-chain bridge will automatically generate a one-time address (One Time Address, OTA).
The user sends an ordinary transaction (such as transferring 0.5 BTC) to the one-time address, Storeman Group will automatically parse the transaction, and perform multi-party signatures (sMPC) through at least 17 cross-chain nodes in the group of 25 Storemans to complete the transaction. Withdrawal of funds from a one-time address.
Storeman Group once again used multi-party signatures (17/25) to cast a mapped asset (wanBTC) on the Ethereum target address specified by the user. In this way, a complete cross-chain is completed.
The above are some of the outstanding highlights of Wanchain’s “Pledged Deposit Sharing Multi-chain Mutual Crossing” mechanism. Of course, the advantages of Wanchain’s cross-chain mechanism are not limited to this. The mechanism is in terms of security, fairness, efficiency, and ease of use. All have carried out in-depth design and implementation.
If you want to learn more about Wanchain’s cross-chain mechanism, you can visit our online documentation .
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