Wanchain — Multi-chain Bridges Is Live On Mainnet Featured With BTC-Ethereum Direct Bridge And Shared Staking Assets

Bryan
Wanchain
Published in
9 min readFeb 26, 2021

On February 26, 2021, the Wanchain team successfully released a brand-new version of cross-chain mechanism — Universal Multi-chain Bridges with Shared Staking Assets after four-months of research and development since Wanchain 5.0. Compared to the previous cross-chain mechanism, the two most prominent highlights of the Multi-chain Bridges are:

  1. The shared staking assets, that is, all the wanBridges’ staking assets are shared in the same collateral pool;
  2. The BTC-Ethereum direct bridge, that is, BTC can be directly cross-chain transferred to Ethereum without Wanchain as a router.

The latest version of WanDesktop Wallet (V1.5.0) now supports the Multi-chain Bridges mechanism. The latest version of WanWallet Desktop is available for download right now! After the next Storeman Group enters the working status on March 9, you can directly cross-chain transfer your BTC from Bitcoin to Ethereum.

Here is the download link of WanWallet Desktop:

Highlighted Features of Universal Multi-chain Bridges with Shared Staking Assets

1. A Storeman Group with shared staking assets enables management of all wanBridges

For Wanchain 5.0, there is a one-to-one correspondence between a wanBridge and a Storeman Group. Therefore, to connect any two public chains, at least one Storeman Group must be created between the two. Under this mechanism, if a Storeman node wants to participate in multiple wanBridges of connecting different public chains, the node operator must run multiple Storeman nodes in different Storeman Groups. Obviously, this situation increases the difficulty of operation for node operators. The deposit funds among different Storeman Groups are independent and cannot share the cross-chain quotas with each other. So, the utilization rate of the deposits is low, which results in the intensive economic bandwidth of busy wanBridges and wastes economic bandwidth of leisure wanBridges. Theoretically, this mechanism has a small security risk of collusion among Storeman nodes. (The left part of the picture below shows the Wanchain 5.0 cross-chain mechanism).

For the reasons above, considering the efficient utilization of resources, the improvement of cross-chain security and the optimization of user convenience, the Wanchain cross-chain mechanism has undergone one more major upgrading on the basis of 5.0. The new version of the cross-chain mechanism is called Universal Multi-chain Bridges With Shared Staking Assets, referred to as “Multi-chain Bridges” for short.

The Multi-chain Bridge mechanism is a novel cross-chain solution proposed by the Wanchain team to provide a high level of security and scalability. In this new mechanism, all wanBridges are run by a combined Storeman group with a shared staking collateral pool. This design reduces the complexity of the cross-chain process and ensures that all the cross-chain assets can freely “flow” between any chains. Moreover, it increases the maximum cross-chain capacity of a single bridge in security precondition. (The right part of the picture below shows Wanchain’s brand-new cross-chain mechanism “Multi-chain Bridges”).

How can the staking assets from different Storeman nodes be used as the common collateral and be shared among multiple wanBridges?

In the Multi-chain Bridge mechanism, once the Storeman nodes stake their assets to the wanBridges, those staked assets will be calculated into a common collateral pool for all bridges. Currently, the only supported type of staked asset is WAN, and support for multiple crypto assets in the future is also being considered by our team. The amount of collateral for a wanBridge is determined by the token price and the quantity of all assets in that Storeman Group where this wanBridge is. As the staking assets of the collateral are shared by all bridges, the cross-chain quota for each wanBridge is also shared by all bridges.

Let’s take a look at a specific example to illustrate the dynamic adjustment of the cross-chain quota for each bridge based on the shared staking assets mechanism. (To make it easier to explain, we simplified some complicated factors in the example below):

Assuming that the Storeman Group supports three wanBridges: BTC-Ethereum, Ethereum-Wanchain, and BTC-Wanchain. The total staking amount of the group is 1,500K WAN (assuming 1WAN=1USDT, and the WAN price stays the same). The collateral rate of the group is 150%.

In the initial stage, BTC-Ethereum, Ethereum-Wanchain, and BTC-Wanchain share the common staking assets which are equivalent to 1,500K USDT, and the maximum cross-chain quota for each bridge is 1,000K USDT (because the collateral rate of the group is 150%).

After a period of time, there are 200K USDT worth of BTC cross-chain transferred from the Bitcoin network to Ethereum, and 600K USDT worth of ETH cross-chain transferred from Ethereum to Wanchain.

Finally, the three bridges, BTC-Ethereum, Ethereum-Wanchain and BTC-Wanchain, still share the collateral amount equivalent to 1500K USDT. However, due to the cross-chain transfer of 200K USDT worth of BTC and 600K USDT worth of ETH, the remaining cross-chain quota for each bridge is 200K USDT worth of tokens.

In short, compared to the previous version of the cross-chain mechanism, an important feature of the “Multi-chain Bridges” mechanism is that the staking assets can be shared among all cross-chain bridges, so the cross-chain quota is allocated on demand, and is reasonably and dynamically allocated to the wanBridges with higher demands for cross-chain transfer.

2. BTC-Ethereum Direct Bridge enables direct cross-chain transfer of BTC from the Bitcoin blockchain directly to Ethereum

For the previous cross-chain mechanism in Wanchain 5.0, all crosschain transfers supported by Wanchain were about transferring assets through Wanchain. In the Multi-chain Bridges, a direct bridge way for the cross-chain mechanism has come into play. The direct bridge supports asset transfer between two blockchains without the need of routing through Wanchain. This allows Wanchain to provide a technical mechanism to bridge Bitcoin, Ethereum, Polkadot, and EOS blockchains directly. For example, we build a direct bridge between Bitcoin and Ethereum for the direct cross-chain transfer of BTC:

“BTC@Bitcoin->wanBTC@Ethereum”

This is to transfer native Bitcoin from the Bitcoin blockchain to ERC-20 wanBTC on the Ethereum Blockchain. wanBTC can then be used for DeFi applications on the Ethereum blockchain that support the ERC-20 token format.

The following picture shows Wanchain’s Multi-chain Bridges:

In the vast ocean of cross-chain cryptocurrencies, there are floating islands, beautiful but isolated. Each island represents a chain. Due to the barrier of the ocean, those islands are isolated from each other. Reflected in the crypto world, each chain has their own different underlying frameworks, data structures, and APIs. Therefore, connecting one chain with another chain, especially for heterogeneous chains (those with significantly different technical infrastructure), is a major challenge.

Wanchain aims to build a decentralized cross-chain infrastructure to connect the whole world since its inception. In the past few years, Wanchain has built cross-chain bridges, that is wanBridges, between different islands through continuous progress of cross-chain technology. Right now, all wanBridges are managed by a common Storeman Group (the number of Storeman Groups can be adjusted as needed). The Storeman Group is composed of 21 open and decentralized Storeman nodes (the number of Storeman nodes can be adjusted as well). With the scientific and reasonable security mechanisms and economic incentive models, the entire cross-chain system runs smoothly and brings the development and prosperity of the cross-chain ecosystem.

We have added an extremely important wanBridge at this time, namely the Bitcoin-Ethereum direct bridge, so that BTC assets can be directly cross-chain transferred to Ethereum without routing via Wanchain.

Based on the Bitcoin-Ethereum direct bridge, it is easier for users to transfer BTC directly from the Bitcoin network to Ethereum, and it also saves on cross-chain fees. But, how does it work?

We might as well compare the workflow differences between the previous cross-chain mechanism and the new Multi-chain Bridges mechanism for the case of transferring BTC from the Bitcoin network to Ethereum.

For the previous cross-chain mechanism, let’s assume that the Storeman Group between Bitcoin and Ethereum is called SG1, and the Storeman Group between Wanchain and Ethereum is called SG2. The workflow of transferring BTC from the Bitcoin blockchain to the Ethereum blockchain follows the steps below:

Step1: The User initiates a BTC cross-chain transaction on the Bitcoin blockchain;

Step2: SG1 locks the BTC on the Bitcoin blockchain after receiving this event and then mints the same amount of wanBTC for the user on Wanchain;

Step3: The user initiates a wanBTC cross-chain transaction on the Wanchain blockchain;

Step4: SG2 locks the wanBTC on Wanchain blockchain after receiving this event and then mints the same amount of wanBTC for the user on Ethereum.

In the above procedure, a total number of 4 transactions are required, including 1 transaction on the Bitcoin blockchain, 2 transactions on Wanchain, and 1 transaction on Ethereum. Among these 4 transactions, the user is required to send 2 transactions — 1 transaction on the Bitcoin blockchain and 1 transaction on Wanchain.

With the adoption of Multi-chain Bridges, the workflow becomes very simple. Let’s assume the combined Storeman Group called SG:

Step1: The user initiates a BTC cross-chain transaction on the Bitcoin blockchain;

Step2: SG locks BTC on the Bitcoin blockchain after receiving this event and then mints the same amount of wanBTC tokens for the user on Ethereum

In the above procedure, a total number of 2 transactions are required, including 1 transaction on the Bitcoin blockchain and 1 transaction on Ethereum. Among the 2 transactions, the user is required to send only 1 transaction on the Bitcoin blockchain. For the user’s perspective, this simplifies the operation steps and saves cross-chain gas fees.

Comparison Between the Old Cross-chain Mechanism and New Cross-chain Mechanism

Compared with the previous version of the cross-chain mechanism, the brand-new Universal Multi-chain Bridges With Shared Staking Assets has made major improvements and enhancements in regards to technology, ordinary users, and node operators. The following table shows the advantages of the new cross-chain mechanism.

WanWallet Desktop, wanBridge Web Supports Direct Cross-chain Transactions of BTC

In terms of the cross-chain mechanism upgrade, the Wanchain development team has also made corresponding updates to our Wanchain Wallets, making enabling Multi-chain Bridges and the Bitcoin-Ethereum direct bridge function. After the next Storeman Group enters the working status on March 9th, users can directly cross-chain transfer their BTC from Bitcoin to Ethreum via WanWallet Desktop or wanBridge Web.

Direct Cross-chain Transactions of BTC on the WanWallet

Let’s take the WanWallet Desktop as an example (wanBridge Web is similar).

Download the latest version of WanWallet Desktop V1.5.0.

Open WanWallet Desktop, go to Cross Chain -> More Tokens, and check the star Bitcoin<->Ethereum. The direct cross-chain function for BTC to Ethereum is on.

Go to Cross Chain -> BTC -> Bitcoin<->Ethereum. The BTC@Bitcoin->wanBTC@Ethereum window pops up. Here are the relevant parameters as follows:

  • Balance: the balance of the BTC address from which you want to cross-chain transfer
  • Storeman Group: Select a Storeman Group. The active group is set by default. In general, you don’t need to choose.
  • Capacity Left: The remaining cross-chain quota. Your cross-chain amount must be less than this amount.
  • To (Ethereum): The recipient address on Ethereum that receives wanBTC
  • Estimated Fee: The total amount of gas fees estimated in the cross-chain process (currently Storeman nodes do not charge cross-chain service fees)
  • Amount: The amount of BTC that you want to cross-chain transfer
  • You Will Receive: The amount of wanBTC that you will receive on Ethereum
  • Advanced Options: The Gas Price can be set in the advanced options. In general, the default value is sufficient.

For updates regarding the Multi-chain Bridge mechanism, please follow Wanchain’s official channels such as Medium and Twitter. We will release the latest progress and disclose more details in due time!

About Wanchain

Wanchain is the infrastructure connecting the decentralized financial world. Wanchain’s live cross-blockchain solution is EVM-based, includes optional private transactions, and provides a decentralized, permissionless, and secure approach for interoperability. Wanchain has employees globally with teams in China, the USA, and other team members around the world in Asia, Africa, and Europe.

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