Paper 2025/184 Original: eprint.iacr.org/2025/184 ↗

NodeChain: Cheap Data Integrity Without Consensus

Abstract

Blockchains enable decentralised applications that withstand Byzantine failures and do not need a central authority. Unfortunately, their massive replication requirements preclude their use on constrained devices. We propose a novel blockchain-based data structure which forgoes replication without affecting the append-only nature of blockchains, making it suitable for maintaining data integrity over networks of storage-constrained devices. Our solution does not provide consensus, which is not required by our motivating application, namely securely storing sensor data of containers in cargo ships. We elucidate the practical promise of our technique by following a multi-faceted approach: We (i) formally prove the security of our protocol in the Universal Composition (UC) setting, as well as (ii) provide a small-scale proof-of-concept implementation, (iii) a performance simulation for large-scale deployments which showcases a reduction in storage of more than $1000$x compared to traditional blockchains, and (iv) a resilience simulation that predicts the practical effects of network jamming attacks.