Zero-knowledge proofs coming to Bitcoin, overhauling network state validation


bitcoin (BTC) users will soon be able to use zero-knowledge proofs (ZK proofs) to speed up the verification process of individual blocks and eventually the entire blockchain.

The ZeroSync Association, a Swiss-based nonprofit, is developing tools that allow users to validate the status of the Bitcoin network without having to download the blockchain or rely on a third party for verification.

ZeroSync was formed to develop and maintain open source software that enables succinct ZK proofs on the Bitcoin blockchain. The group uses StarkWare property Zero Knowledge Scalable Transparent Knowledge Argument (zk-STARK) validity tests to generate ZK proofs for the Bitcoin network.

The tool promises to overhaul the verification process of the Bitcoin blockchain, which still requires node operators to download a large amount of data to synchronize the correct state of the Bitcoin network.

ZeroSync is using ZK proofs to generate valid proofs and check the latest state of the blockchain almost instantly.

ZK tests have been a revelation for the Ethereum ecosystem, with several test methods powering various Layer 2 scaling platforms, including Polygon, Arbitrum, Optimism, and StarkNet.

Related: Polygon Ethereum-scaling zkEVM beta 'holy grail' hits mainnet

An announcement from the ZeroSync Association highlights ZKP's promise for blockchain scalability and privacy by providing "nearly fixed-size" proofs that verify large computations.

The project's work is pioneering the application of ZKP to the Bitcoin network, and the organization describes the relative simplicity of Bitcoin and the UTXO model as a unique value proposition for the application of recursive tests.

The ZeroSync Association also notes that the ZKP tools do not require consensus changes or additional trust assumptions for the Bitcoin network and its users. The organization is creating a software development kit (SDK) that will allow developers to build custom validity tests for specific use cases without requiring extensive domain expertise.

ZeroSync is in the process of creating a client for fast initial block download (IBD), as well as implementing the first full proof of Bitcoin consensus. The client will allow users to sync a full node without making any code changes to Bitcoin Core.

ZeroSync is using the Cairo programming language, pioneered by StarkWare to create STARK testable programs for computations.

The ZeroSync tool is currently in a prototype state, but has the ability to test the validity of individual blocks assumed to be valid, which check all Bitcoin rules except scripts. The team also has an in-browser demo that works. checker for STARK testing of Bitcoin blocks.

The ZeroSync Association was initially funded by Geometry and StarkWare, but is establishing a non-profit entity to enable continued development and maintenance by stakeholders within the Bitcoin community.

A statement from StarkWare president and co-founder Eli Ben-Sasson, who co-invented zk-STARKS, summed up the magnitude of ZKP pouring into the Bitcoin ecosystem:

โ€œAfter years of frustration with slow syncing, users will be able to sync with the network much faster and with less computation. It's a technological leap similar to the transition of the Internet from slow dial-up to high-speed broadband."

Lightning Labs, the team behind Bitcoin layer 2 lightning network payment system, is a contributing partner to the ZeroSync project.

The company intends to use ZeroSync to power compressed transaction history testing for its Taproot asset rendering overlay (Taro) protocolwhose objective is to promote the issuance of digital assets in the Bitcoin block chain.