Paper 2025/645

GIGA Protocol: Unlocking Trustless Parallel Computation in Blockchains

Abstract

The scalability of modern decentralized blockchain systems is constrained by the requirement that the participating nodes execute the entire chains transactions without the ability to delegate the verification workload across multiple actors trustlessly. This is further limited by the need for sequential transaction execution and repeated block validation, where each node must re-execute all transactions before accepting blocks, also leading to delayed broadcasting in many architectures. Consequently, throughput is limited by the capacity of individual nodes, significantly preventing scalability. In this paper, we introduce GIGA, a SNARK-based protocol that enables trustless parallel execution of transactions, processing non-conflicting operations concurrently, while preserving security guarantees and state consistency. The protocol organizes transactions into non-conflicting batches which are executed and proven in parallel, distributing execution across multiple decentralized entities. These batch proofs are recursively aggregated into a single succinct proof that validates the entire block. As a result, the protocol both distributes the execution workload and removes redundant re-execution from the network, significantly improving blockchain throughput while not affecting decentralization. Performance estimates demonstrate that, under the same system assumptions (e.g., consensus, networking, and virtual machine architecture) and under high degrees of transaction parallelism (i.e., when most transactions operate on disjoint parts of the state), our protocol may achieve over a 10000x throughput improvement compared to popular blockchain architectures that use sequential execution models, and over a 500x improvement compared to blockchain architectures employing intra-node parallelization schemes. Furthermore, our protocol enables a significant increase in transaction computational complexity, unlocking a wide range of use cases that were previously unfeasible on traditional blockchain architectures due to the limited on-chain computational capacity. Additionally, we propose a reward mechanism that ensures the economic sustainability of the proving network, dynamically adjusting to computational demand while fostering competition among provers based on cost-efficiency and reliability.