Highlights and Interaction Tutorial of Webb Protocol, a Privacy Cross-Chain Protocol that Raised $7 Million in Funding

Author: Xiyou, ChainCatcher

On May 8, the privacy cross-chain protocol Webb Protocol announced the completion of a $7 million seed round financing, co-led by Polychain Capital and Lemniscap.

With the backing of well-known capital and large funds, Webb Protocol has also become a hot topic of interest in the crypto community. According to the crypto data platform Rootdata, Webb Protocol recently ranked second in search popularity, with the Sui network taking the top spot.

This raises curiosity about why this relatively unfamiliar cross-chain product, which only gained attention due to its financing, has garnered such high interest.

In fact, the Webb Protocol privacy cross-chain protocol is not a cross-chain bridge; it is a cross-chain infrastructure that has developed the cross-chain network Tangle Network and the privacy cross-chain bridge Hubble Bridge based on zero-knowledge proof technology.

So, how does Webb Protocol differ from previous cross-chain products? What is the principle behind the privacy cross-chain bridge Hubble Bridge? What is the user experience like?

What is Webb Protocol? What are its highlights?

Webb Protocol (abbreviated as Webb) is a privacy cross-chain infrastructure designed for a multi-chain world. It has developed a series of privacy tools and protocols based on technologies such as zero-knowledge proofs (ZK) and multi-party computation (MPC) solutions, aiming to provide new privacy standards for cross-chain applications, assets, data, and location information. The platform was co-founded by Drew Stone, a co-founder of Commonwealth Labs (a decentralized community management platform).

From this perspective, Webb is not a cross-chain bridge but rather an underlying infrastructure for building cross-chain bridges, capable of achieving private message transmission. Developers can integrate or build cross-chain privacy applications based on the tools and facilities provided by the Webb protocol.

The core foundational component of the Webb protocol is actually Tangle Network, a blockchain built on multi-party computation (MPC) technology, primarily providing bridging and messaging functions.

Tangle Network is an independent chain constructed by Webb based on Substrate (a blockchain development framework), aiming to provide users with cross-chain-related services. It hopes to bridge any blockchain networks developed on EVM, Substrate, and Cosmos, enabling information transmission between different networks.

Simply put, Tangle Network serves as a bridge (intermediate chain) built across different blockchain networks, allowing for information transmission between them through bridging. It can achieve not only asset privacy cross-chain but also application cross-chain.

Synchronizing messages on the Tangle Network

The relationship between Webb and Tangle Network can also be understood as Webb being a privacy cross-chain underlying technology infrastructure tool built on the Tangle network, with the cross-chain message transmission part implemented by Tangle Network.

Specifically, the relayer on Tangle Network is responsible for message transmission and verification between different chains. Once the bridged information passes verification, it will be signed through DKG (Distributed Key Generation) and synchronize the bridge information updates.

Currently, developers can build privacy cross-chain applications based on the Tangle Network blockchain developed by Webb, such as privacy cross-chain bridges, privacy identity verification applications, and privacy swaps.

Hubble Bridge Privacy Cross-Chain Bridge

The privacy cross-chain bridge Hubble Bridge is the first user-facing use case built by Webb based on Tangle Network, primarily used for transferring tokens between different blockchains in a private manner. It obfuscates users' cross-chain transaction history by using zero-knowledge proofs.

Currently, in the market, the transfer information of assets between different blockchains is generally public, allowing anyone to track users' transactions and potentially use this information to uncover their real identities. However, users have privacy needs for cross-chain transactions, and the most well-known privacy transaction application is the Ethereum-based mixer Tornado Cash, which only supports asset privacy transactions on the Ethereum single chain and does not support cross-chain asset expansion. Webb aims to enhance the privacy of cross-chain applications through zero-knowledge proof technology, such as hiding relevant transaction information like the source chain, cross-chain amount, and target chain address during the cross-chain process.

To this end, Webb provides an Anchor System, an interoperable privacy system based on zero-knowledge proofs, primarily used for transferring assets privately between different blockchains. The Anchor System can bridge and track the Merkle Tree data in the block headers of different blockchain networks. At the same time, it uses zero-knowledge proofs to obfuscate users' transaction history.

The specific cross-chain implementation principle is that Hubble Bridge is built on the Tangle Network cross-chain network, bridging the block header data of source chain A and target chain B through the Anchor System. When a cross-chain transaction request is initiated, the Anchor System receives this block data, encrypts the transaction information, and then forwards this cross-chain request information through the Tangle Network relayer, which verifies the authenticity of the information. Once verified, it will notify the target chain B to receive or withdraw assets.

For example, if Xiaoming wants to transfer 10 ETH from Polygon to the Arbitrum chain, he initiates a request to transfer 10 ETH on Polygon, which needs to be wrapped into 10 webbETH on the target chain and stored in a privacy pool that does not display the specific asset name. The Anchor System can synchronize this 10 ETH request data to the Arbitrum chain, and after verification, Xiaoming's operation is valid. He can use the transaction data to transfer these webbWETH assets or a portion of them to a new privacy address public key, and the type of transferred assets can be hidden. Later, he can unwrap the webbWETH to other addresses (similar to the mixer Tornado Cash).

At this point, the user involves three addresses: the original address holding the assets ------ transferring to the public key address (privacy address) ------ unwrapping assets to another address, making it impossible to trace the user's transactions.

Currently, the Hubble Bridge test version has been launched, supporting asset transfers and withdrawals between test networks such as Ethereum Goerli, Polygon Mumbai, Arbitrum Goerli, and Avalanche Fuji. Users can experience transferring assets between different blockchains using the test version.

Hubble Bridge Interaction Tutorial (using the example of transferring ETH from the Goerli test network to Arbitrum)

1) Hubble Bridge test network (https://app.webb.tools/#/bridge). Connect to the Metamask wallet and switch to the Goerli network. Users need to create a NoteAccount (used to connect to the MetaMask wallet address public key);

2) Wrap and Deposit assets. Select the source chain and target chain, input the cross-chain asset amount, and submit. This will wrap the cross-chain assets into webb assets, such as wrapping ETH into webbETH.

It is important to note that when submitting the deposit, a Spend note will be generated, which needs to be copied. This spend note records the details of each transaction (such as private key, transfer amount), and users need to keep it confidential, as anyone holding this information can withdraw the user's funds from the bridge. Additionally, this transaction information is recorded on-chain and will also be stored on the local computer hard drive. Users can use it to manage their assets.

3) Privacy transfer. Before transferring, users can create another privacy address, such as logging in with another wallet and creating an account, recording the public key;

Select the transfer token and target chain, input the amount, and enter the recipient's public key address, then click Transfer;

4) Unwrap and withdraw assets. Users can unwrap cross-chain assets to other assets or addresses, select the token, unwrap asset type, amount, remaining assets, and receiving address (can fill in a new receiving address).

Thus, users can transfer assets between different addresses through Hubble Bridge.

Additionally, since Hubble Bridge is currently still in the testing phase, users may encounter some functionalities that are not available during the interaction process.