Bitcoin Blockchain Verification and Scalability to be Revolutionalized
The ZeroSync Association is developing tools using zero-knowledge proofs (ZK-proofs) to expedite the verification process for the Bitcoin blockchain, potentially enhancing scalability, privacy, and efficiency without requiring consensus changes or additional trust assumptions
Bitcoin users may soon benefit from zero-knowledge proofs (ZK-proofs) to expedite the verification process of individual blocks and, eventually, the entire blockchain. ZeroSync Association, a Swiss-based nonprofit, is developing tools to enable users to validate the state of the Bitcoin network without downloading the blockchain or trusting third-party verification.
The ZeroSync Association focuses on developing and maintaining open-source software that incorporates succinct zero-knowledge proofs (ZKPs) into the Bitcoin blockchain. The organization uses StarkWare's proprietary zero-knowledge Scalable Transparent Argument of Knowledge (zk-STARK) validity proofs to generate ZKPs for the Bitcoin network. This development aims to revolutionize the Bitcoin blockchain verification process, which currently requires node operators to download large amounts of data to synchronize the network's correct state.
ZKPs have already transformed the Ethereum ecosystem, with various proof methods powering layer-2 scaling platforms like Polygon, Arbitrum, Optimism, and StarkNet. The ZeroSync Association emphasizes the potential of ZKPs for blockchain scalability and privacy, providing 'almost-fixed-size' proofs for verifying large computations.
Applying ZKPs to the Bitcoin network is a pioneering move, with the organization describing Bitcoin's simplicity and UTXO model as an ideal environment for recursive proofs. The ZeroSync Association also points out that ZKP tools do not necessitate consensus changes or additional trust assumptions for the Bitcoin network and its users. To facilitate developers, the organization is creating a software development kit (SDK) that will allow them to generate custom validity proofs for specific use cases without requiring in-depth domain expertise.
ZeroSync is currently building a client for fast initial block download (IBD) and working on the first full proof of Bitcoin consensus. This client will enable users to sync a full node without making any code changes to Bitcoin Core. The project utilizes the Cairo programming language, developed by StarkWare, to create STARK-provable programs for computations.
The current prototype of ZeroSync's tool can prove the validity of individual assumed valid blocks, verifying all Bitcoin rules except for Scripts. The team also offers a working in-browser demo verifier for STARK proofs of Bitcoin blocks. Initially funded by Geometry and StarkWare, the ZeroSync Association is establishing a non-profit entity to facilitate ongoing development and maintenance from stakeholders within the Bitcoin community.
Eli Ben-Sasson, StarkWare president and co-founder who co-invented zk-STARKS, highlighted the importance of ZKPs coming to the Bitcoin ecosystem:
“After years of frustration about slow syncing, users will be able to sync with the network much faster, and with less computation. It’s a technological leap akin to the transition from slow dial-up internet to high-speed broadband.”
Lightning Labs, the team behind the Bitcoin layer-2 Lightning Network payment system, is a contributing partner to ZeroSync's project. The company plans to use ZeroSync to power compressed transaction history proofs for its Taproot Asset Representation Overlay (Taro) protocol, aiming to enable the issuance of digital assets on the Bitcoin blockchain.
