7.2 Applications of Chain State Proofs
Last updated
Last updated
6.2.1 Accelerating Initial Sync
A typical application of chain state proofs is to accelerate the initial block download process in Bitcoin Core. In essence, users can synchronize in three steps: validate the current chain state using proofs, download the corresponding Unspent Transaction Output (UTXO) set (about 5GB of data), copy it to the "chainstate" folder, and run Bitcoin Core as usual. This process allows users to bootstrap a full node without needing to download and verify the entire 500GB historical blockchain. It reduces the initial synchronization time from multiple hours (or even days) to a few minutes.
Combining Utreexo blocks with chain state proofs can achieve even faster sync. While chain state proofs allow skipping initial block download, with Utreexo blocks, nodes may not even need to download the UTXO set. After verifying the chain state proof, Utreexo nodes can immediately start listening for new blocks. The drawback is that Utreexo requires providing Merkle inclusion proofs for all UTXOs used in a block, resulting in an additional cost of about 2 megabytes per block. However, bridging nodes are not necessary. Utreexo nodes can compute their own UTXO inclusion proofs from incoming blocks, making these methods highly suitable for bandwidth-constrained environments.
6.2.2 Iterative Applications of ZKPs in Bitcoin
The SATPORT team has identified several areas where ZKPs can further be applied within the Bitcoin realm. For instance, significantly enhancing the privacy of the Lightning Network. Routing nodes need to publicly announce their UTXOs in point-to-point (p2p) propagation protocols, potentially linking them to their IP addresses. Leveraging zero-knowledge proof technology can extend chain state proofs to prove the validity of payment channels without sacrificing privacy.
This also includes applications of privacy credentials, where custodians like exchanges can prove their solvency to their clients. Chain state proofs transform a simple blockchain into an identity-verified data structure capable of efficiently answering complex queries through verifiable responses. Chain processing proofs can often serve as adapters to create indexes on blockchain data, applying various filters or data transformations.
The above-listed examples represent only a fraction of the potential applications of ZKPs within the Bitcoin environment. The potential of zero-knowledge proofs reaches far beyond these instances. As technology evolves, we can anticipate a multitude of innovative applications for zero-knowledge proofs in the Bitcoin network, including enhanced privacy protection, optimized data queries, and a wide range of trusted cross-chain interactions.
