Emery: CENNZnet- Ethereum bridge
We are excited to announce the upcoming launch of our very own two-way token bridge: Emery! Emery connects CENNZnet to Ethereum allowing our community to easily transfer ERC-20 tokens, Native ETH, data and assets (like NFTs) between the two chains.
The Emery bridge unlocks all sorts of new channels of liquidity and pools of users for DApps on CENNZnet. It also allows both chains to read and cryptographically verify information from the connected chain, meaning both chains will recognise that a user holds certain assets and even allows composability of DApps.
This guide will explain:
- What a token/blockchain bridge is
- The benefits of the Emery bridge for the CENNZnet community
- How the Emery bridge works
What is a token bridge?
A token bridge or blockchain bridge is a connection that allows the transfer of tokens and/or arbitrary data from one blockchain to another. The really clever thing about a successful bridge is that the connected chains can each have totally different governance models, protocols and rules; something which would typically totally cut them off from each other. Despite their different core protocols, the bridge allows the chains to interact and interoperate securely and quickly.
Bridge technology introduces the possibility of a world of connected blockchains. Bridges can connect multiple chains, each with their own focus and strengths, enabling complex and efficient inter-chain actions – all within a totally decentralised state. Rather than blockchains developing in isolation, as is the case today, chains and decentralised communities will be able to interact and develop together.
What are the benefits of Emery?
The Emery bridge brings many benefits to the CENNZnet community:
- Secure way to transfer tokens: Transferring tokens from CENNZnet to Ethereum and vice versa is now seamless and secure. The bridge provides a decentralised and cryptographically designed way to move tokens and assets between the two chains. Token holders no longer need to rely on the clunky and insecure process of using centralised exchanges.
- Improving liquidity: The bridge unlocks more liquidity for the CENNZnet community. Devs and creators can now make use of CENNZnet’s low gas fees and fast transaction speeds to run DApps or mint NFTs, but receive payments in Ethereum supported currency as well as CENNZ.
- New cross-functionality possibilities: Connecting blockchains means you can combine their strengths. In this case, Ethereum’s vibrant community and popular token with CENNZnet’s ease of use and low fees. This opens up a whole new world of cross-functionality possibility e.g gameplay on CENNZnet (something which gas fees prevent on Ethereum) and then have game assets recognised on Ethereum.
- Become part of the wider decentralised world: With bridges, blockchain’s will no longer be islands that cannot interact. By becoming part of the broader blockchain community we embrace more of the decentralised world and make blockchain more powerful.
How does the bridge work?
Emery works by utilising the CENNZnet network validators, chosen by the network-wide Proof of Stake mechanism. As well as being responsible for creating blocks on CENNZnet, validators are now required to verify bridge transactions. They have the authority to act as notaries, verifying the authenticity of a deposit to a bridge contract.
The security of this system is based on threshold cryptography alongside a system of smart contracts. It works something like this:
Process for Ethereum to CENNZnet transactions:
1. The user sends a deposit to a bridge contract on Ethereum containing:
- The recipient CENNZnet address
- The deposit amount
- ERC20 token address (or native ETH)
2. The user then sends a deposit claim to the CENNZnet bridge module with their Ethereum transaction receipt to initiate the claim of funds on CENNZnet.
3. The CENNZnet Bridge module waits for block confirmations on Ethereum. Validators query block hashes against Ethereum’s full node to check they are valid. If the Proof is valid they create and submit a notarisation claim against the deposit.
4. After all relevant claims are made by the validators a deposit is enacted. We only wait for at least 2/3rds of validators to notarise a deposit successfully. And some number of block confirmations to protect against Ethereum reorgs. The token information is then pulled from the Ethereum contract and the correct amount is minted to the nominated CENNZnet address.
The whole secure process will only take a couple of minutes.
CENNZnet to Ethereum transaction:
1.A user sends a ‘withdraw’ transaction to the CENNZnet bridge module containing:
- Recipient Ethereum address
- Asset Id
2. Validators sign a message saying “CENNZnet locked these tokens” and issue a withdrawal proof.
3. The user (or anyone) can submit the withdrawal proof to the Ethereum contract. This checks the signatures are legitimate and releases the tokens to the intended recipient address.
Note: while these examples show the process for token transfer, the method also works for moving events from one chain to another, for example DAO votes.