Abstract: In cloud computing, frequent data updates and migrations by data owners (DO) raise data management complexity and challenge traditional cloud data auditing. Traditional third-party auditor (TPA) based dynamic auditing has centralization and single-point failure issues. Although blockchain technology is adopted to replace TPA, current blockchain-based schemes suffer from high computational cost, low dynamic efficiency, and heavy DO auditing burden. Thus, a Dynamic Cloud Data Auditing Scheme empowered by Side Information and Consortium Blockchain Smart Contracts(DCASIC) is proposed. DCASIC decouples auditing metadata from data block indexes via side information auditing and correlates them with a homomorphic hash function, enhancing dynamic auditing efficiency. Smart contract parallel execution and pre-computed verification information reduce DO auditing time. Theoretical and experimental results show DCASIC significantly cuts computational cost, boosts dynamic auditing efficiency, and reduces DO time cost during auditing compared with existing blockchain-based schemes.

摘要： 在云计算环境中，数据拥有者（DO）频繁的数据更新是常态，这种动态性不仅提高了数据管理的复杂性，也给传统的云数据审计带来了很大的挑战。传统上，云数据动态审计通常依赖第三方（TPA）进行。然而，TPA存在中心化、单点故障等问题。为了解决这些问题，许多研究开始使用区块链技术代替TPA进行审计，但当前依赖区块链的动态审计方案大都存在计算开销大、动态效率低、DO审计负担重等问题。基于此，提出了一种侧信息和联盟链智能合约赋能的动态云数据审计方案（DCASIC），通过审计侧信息（SI）将审计元数据和数据块索引解耦，并通过同态哈希函数将其相互关联，提升了动态审计操作的效率。其次通过智能合约的自动并行执行和对验证审计的信息预计算，减少DO的审计时间开销。最后，从理论和实验角度验证了与当前基于区块链的动态云审计方案相比，DCASIC能够显著降低审计阶段的计算开销、提高动态审计的效率，以及审计阶段DO的时间开销。