A Scalable Layer 2 Off-Chain Protocol for Blockchain Using Ethereum Rollups

Abstract

The two biggest problems facing modern blockchain systems are scalability and privacy. The system's capacity to scale is constrained by the need to process transactions at each node. In addition, despite all other benefits, a widely cited barrier to blockchain adoption is the requirement to disclose all transaction data at every node, thereby making the data public. In order to overcome these two issues, we introduce the ScaZK (Scalable Zero Knowledge) protocol, which primarily makes two contributions: (i) In order to improve performance, we propose a new, lightweight protocol that uses non-interactive proofs for off-chain calculations, which limits on-chain computational efforts to the verification of execution accuracy rather than actual execution. Private data utilised in the off-chain computation does not need to be made public in order to verify correctness because of the verifiable computation scheme's zero-knowledge property. (ii) We present a framework for defining, integrating, and deploying these off-chain calculations. It includes a compiler, proof and verification generators, and a domain-specific language for smart contracts. It hides the considerable complexity that zero-knowledge proofs entail, offers developers a more comfortable and advanced level of programming abstractions, and allows circuit integration, which promotes adoption. Our contributions in this work specifically include: (i) a novel proof bucketing compression scheme, (ii) integration of a B+ Merkle Tree for efficient rollup root computation, (iii) parallel off-chain execution for throughput scalability, and (iv) partial zkEVM compatibility for developer accessibility. We also present stress testing, fault recovery analysis, and gas breakdown for multiple proof systems to validate the protocol's resilience and scalability.