Guppy: Efficient Light Clients via Recursive Zero-Knowledge Proofs
Guppy lets blockchain light clients verify full state via recursive zero-knowledge proofs without validators maintaining state commitments, processing thousands of updates per second.
Guppy is a light-client protocol in which validators commit only to state updates while an off-chain, untrusted service secured by recursive zero-knowledge proofs maintains a verifiable Merkle tree over the full state. A hash-chain commitment moves validator signature verification out of the proving circuit, and a parallel recursive proving pipeline keeps latency growth logarithmic with throughput. A Plonky2-based implementation maintains a tree of size 2^30 while processing thousands of updates per second, adding only 2-4 seconds of latency without increasing block-construction complexity.
- Validators commit only to state updates, not full state trees.
- Off-chain service secured by recursive ZKPs maintains a verifiable Merkle tree.
- Hash-chain commitment moves signature verification out of the proving circuit.
- Plonky2 implementation handles 2^30-entry trees at thousands of updates per second.
- Proving latency grows only logarithmically; added latency is 2-4 seconds.
Full article212 words · extracted from arxiv.org · click to collapse
Traditional light clients rely on validators committing to the entire blockchain state at every block via a state commitment such as a Merkle tree, allowing clients to verify facts using short proofs. However, maintaining large and ever-growing state trees imposes a significant burden on validators and lies on the critical path of block production. As a result, many modern high-throughput chains avoid this approach altogether. This work asks whether efficient inclusion proofs can be supported without requiring validators to maintain full state commitments. We present Guppy, a protocol that achieves this by having validators commit to just the state updates. An off-chain, untrusted service, secured by recursive Zero-Knowledge Proofs (ZKPs), then maintains a verifiable Merkle tree over the full state. This design keeps validator overhead negligible and does not increase the asymptotic complexity of block construction. Our design rests on two key technical ideas. First, a hash-chain commitment moves validator signature verification out of the ZK circuit, keeping the proving circuit efficient. Second, we design a parallel recursive proving pipeline that leverages cheap recursion in modern ZKPs to ensure latency grows only logarithmically with throughput. Our Plonky2-based implementation demonstrates that Guppy can maintain a Merkle tree of size 2^30 while processing thousands of updates per second, adding only 2-4 s of latency.
Text extracted automatically; images, tables and formatting may be missing. Original: https://arxiv.org/abs/2609.07963