Original title: BitVM Just Got A Massive Upgrade
Original author: Guillaume Girard
Original link: https://bitcoinmagazine.com/takes/bitvm-just-got-a-massive-upgrade
An important milestone in the development of Bitcoin's scalability and programmability is BitVM. Based on the BitVM protocol, Bitlayer launched the first version of the Finality Bridge testnet, which is an important step towards Bitcoin’s revival or Bitcoin “Season 2”.
Unlike past BTC bridges that relied on centralized entities or had trust assumptions, Finality Bridge combines BitVM smart contracts, fraud proofs, and zero-knowledge proofs. This combination of technologies not only improves security, but also significantly reduces the need for trust in third parties. Although it has not yet reached the trust-free level of the Lightning Network, it has been significantly improved compared to the existing Bitcoin second-layer sidechain solutions and has greatly expanded the design space of Bitcoin applications.
Finality Bridge operates on the principle that funds are securely locked in addresses managed by the BitVM smart contract, and its operation assumes that at least one participant in the system is honest. This setup inherently reduces the trust requirements, but also comes with the additional complexity of Bitlayer managing this version of the bridge.

Source:https://blog.bitlayer.org/introducing_finality_bridge/
Trust Mechanism Analysis
In fact, when BTC is locked into the BitVM smart contract through Finality Bridge, users will obtain a token YBTC that is strictly 1:1 anchored with Bitcoin. This anchoring is not only a commitment, but is also enforced by the underlying smart contract logic, ensuring that each YBTC corresponds one-to-one to BTC on the main chain. This mechanism allows users to participate in DeFi activities such as lending, borrowing, and liquidity mining in the Bitlayer ecosystem without sacrificing Bitcoin security and settlement guarantees.
While some in the community may have reservations about these activities, this type of architectural design allows users to enjoy guarantees that were not previously available in sidechain designs, and we can achieve this without making any "changes" to Bitcoin itself (although covenants could make the bridge design completely "trust-minimized," effectively making it a "real" Bitcoin layer 2 network). For more detailed information on the risk level of sidechain designs, see Bitcoin Layers' Assessment of Bitlayer.
However, before a true Bitcoin layer 2 network becomes a reality, Bitlayer’s Finality Bridge is the best example of the BitVM2 paradigm, demonstrating the potential that developers can achieve by switching from centralized chains to Bitcoin. While chains based on BitVM will face many challenges, I am excited about the prospect of Bitcoin becoming the ultimate settlement chain for all economic activity in the future.