We are excited to announce that Celer cBridge will expand support for BRC-20 token bridge, enabling seamless interoperability between the Bitcoin ecosystem and the EVM ecosystem. Users will be able to perform cross-chain transfers between BRC-20 and ERC-20 tokens across the Bitcoin network and EVM Chains.
The Dawn of a New Era in BTC Network Interoperability
The motivation behind this expansion is deeply rooted in the recent innovations within the Bitcoin ecosystem, particularly the rise of BRC-20 tokens. These tokens have sparked a phenomenal interest in the community, heralding a new era of possibilities. However, the Bitcoin network, despite being the most secure and valuable network, has been somewhat isolated due to its limitations in supporting Turing-complete smart contracts. This has kept BRC-20 tokens like $ORDI and $SATS from fully participating in the thriving DeFi ecosystems that EVM Chains offer.
Celer cBridge’s initiative to bridge these gaps is more than just a technical solution; it’s a vision to bring together the best of both worlds. The goal is to let BRC-20 tokens flow smoothly and securely into the EVM chain’s rich DeFi landscape, unlocking better liquidity and a superior trading experience for users. This is not just about enabling transactions; it’s about creating a more inclusive, interconnected, and fluid blockchain universe.
The Journey Towards Integration: A Two-Phased Approach
The strategy for implementing a secure and trustless BRC-20 bridge is meticulously planned in two phases.
Phase 1: BRC-20 Bridge based on Celer SGN
The first phase revolves around the Celer State Guardian Network (SGN), a proven PoS network that has been the backbone of over $15 billion in secure cross-chain transactions. Here, we see the initial bridging of BRC-20 tokens using a network that has stood the test of time in terms of security and reliability. Specifically, the SGN-based BRC-20 bridge works as follows:
- For transfers from the Bitcoin network to EVM chains, users first send BRC-20 tokens to an SGN-managed address on the Bitcoin network, and sign a message confirming the bridge details such as the recipient address. Post SGN consensus and verification, an equivalent amount of ERC-20 tokens will be minted on the target EVM chain.
- For transfers from EVM chains to the Bitcoin network, users burn ERC-20 tokens in a smart contract on the EVM chain. Following SGN consensus and verification, an equivalent amount of BRC-20 tokens are released on the Bitcoin network to the user.
The SGN-based BRC-20 bridge is expected to launch in a few weeks.
Phase 2: Elevating Security and Decentralization with Brevis ZK
In the second phase, Celer cBridge will leverage Zero-Knowledge (ZK) proofs to elevate the security and decentralization of BRC-20 cross-chain transfers to unprecedented levels. Specifically, for transfers from the Bitcoin network to EVM chains, a ZK proof will be required to verify Bitcoin’s state and transactions on EVM chains. Unlike traditional zkBridges, building a BRC-20 zkBridge faces additional complexities:
- Post-SegWit, with the separation of witness data from transactions, verifying transaction Merkle inclusion using just a blocker header is insufficient for proving the validity of witness data (integral for BRC-20). Hence, each BRC-20 zkBridge transaction requires a ZK proof to validate the Schnorr signature of the source chain transaction witness data.
- Due to the absence of native smart contracts to validate BRC-20 transactions, currently, centralized third parties provide BRC-20 indexing services. To achieve a trustless BRC-20 zkBridge, a ZK-proved BRC-20 indexer on the EVM chain is necessary, which involves proving all historical BRC-20 transactions – a massive and costly undertaking.
Given these complexities, a trustless BRC-20 zkBridge will require more time and resources. The plan is to gradually implement by partnering with Brevis, a blockchain coprocessor.
Celer cBridge’s expansion to support BRC-20 tokens is a significant step towards integrating the Bitcoin network with EVM chains. This initiative not only enhances the liquidity and usability of BRC-20 tokens but also represents a remarkable advancement in blockchain interoperability. By addressing the unique challenges of bridging these different blockchain technologies, Celer cBridge is paving the way for a more interconnected and efficient digital asset ecosystem.