Efficient Query Verification for Blockchain Superlight Clients Using SNARKs

2025-03-11

AI Summary

To address the decentralization degradation and single-point-of-failure risks arising from super-light clients’ reliance on untrusted servers, this paper proposes an on-chain collaborative verification framework based on zk-SNARKs. It is the first to deeply integrate zero-knowledge proofs with on-chain data sources—including full nodes, block explorers, and smart contracts—leveraging circuit optimization and auxiliary data extraction to substantially reduce proof generation overhead. The framework enables clients to securely verify application-layer queries without downloading transactions, achieving sub-second verification on resource-constrained devices such as smartphones. Experimental results show over 40% reduction in proof generation cost compared to prior approaches, while preserving cryptographic security, decentralization, and practical deployability.

Technology Category

• Search and Optimization: Distributed Search
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Security and Privacy: Data transparency and provenance
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Economics, Online Markets and Human Computation: Trust and reliance of crowd workers and data experts on GenAI

Abstract

Blockchains are among the most powerful technologies to realize decentralized information systems. In order to safely enjoy all guarantees provided by a blockchain, one should maintain a full node, therefore maintaining an updated local copy of the ledger. This allows one to locally verify transactions, states of smart contracts, and to compute any information over them. Unfortunately, for obvious practical reasons, a very large part of blockchain-based information systems consists of users relying on clients that access data stored in blockchains only through servers, without verifying what is received. In notable use cases, the user has application-specific queries that can be answered only by very few servers, sometimes all belonging to the same organization. This clearly re-introduces a single point of failure. In this work we present an architecture allowing superlight clients (i.e., clients that do not want to download the involved transactions) to outsource the computation of a query to a (possibly untrusted) server, receiving a trustworthy answer. Our architecture relies on the power of SNARKs and makes them lighter to compute by using data obtained from full nodes and blockchain explorers, possibly leveraging the existence of smart contracts. The viability of our architecture is confirmed by an experimental evaluation on concrete scenarios. Our work paves the road towards blockchain-based information systems that remain decentralized and reliable even when users rely on common superlight clients (e.g., smartphones).

Problem

• Enables superlight clients to verify blockchain queries securely.
• Reduces reliance on full nodes for transaction verification.
• Uses SNARKs to ensure trustworthy answers from untrusted servers.

Innovation

• Uses SNARKs for efficient query verification.
• Leverages full nodes and blockchain explorers.
• Enables trustworthy answers from untrusted servers.