Depermissioning Web3: a Permissionless Accountable RPC Protocol for Blockchain Networks

TL;DR

This paper introduces PARP, a permissionless, accountable RPC protocol for blockchain networks that ensures data integrity, privacy, and incentivizes full nodes to serve clients reliably, bridging Web3 and Web2 applications.

Contribution

It presents a novel protocol combining light client schemes, fraud proofs, and payment channels to enable permissionless, accountable RPC interactions in blockchain networks.

Findings

Prototype implementation for Ethereum demonstrates feasibility.

Quantifies overhead compared to standard RPC protocol.

Ensures data integrity and incentivizes honest node behavior.

Abstract

In blockchain networks, so-called "full nodes" serve data to and relay transactions from clients through an RPC interface. This serving layer enables integration of "Web3" data, stored on blockchains, with "Web2" mobile or web applications that cannot directly participate as peers in a blockchain network. In practice, the serving layer is dominated by a small number of centralized services ("node providers") that offer permissioned access to RPC endpoints. Clients register with these providers because they offer reliable and convenient access to blockchain data: operating a full node themselves requires significant computational and storage resources, and public (permissionless) RPC nodes lack financial incentives to serve large numbers of clients with consistent performance. Permissioned access to an otherwise permissionless blockchain network raises concerns regarding the privacy, integrity, and availability of data access. To address this, we propose a Permissionless Accountable RPC Protocol (PARP). It enables clients and full nodes to interact pseudonymously while keeping both parties accountable. PARP leverages "light client" schemes for essential data integrity checks, combined with fraud proofs, to keep full nodes honest and accountable. It integrates payment channels to facilitate micro-payments, holding clients accountable for the resources they consume and providing an economic incentive for full nodes to serve. Our prototype implementation for Ethereum demonstrates the feasibility of PARP, and we quantify its overhead compared to the base RPC protocol.