BLA: Byzantine-Tolerant Lazy Auditing Framework for Decentralized Storage Data Integrity

With the rise of blockchain technology, the trend toward decentralization has spread to the field of remote storage, leading to the emergence of decentralized storage as a promising model. This change is highlighted by its features of open and fair access, reduced dependence on intermediaries, and strong privacy protections. However, similar to centralized storage, the decentralization of data management presents challenges, including the separation of ownership and control, along with the need for integrity auditing on externally managed data. The current popular centralized auditing model for the mainstream cloud storage cannot be directly used for decentralized storage environments. Additionally, Homomorphic Verification Tag (HVT)-based auditing models encounter significant problems such as high computational costs and inefficient auditing processes. In response to these needs, we introduce a novel Byzantine-tolerant Lazy Auditing framework (BLA) to ensure data integrity in decentralized storage settings. A key innovation is the hierarchical architecture used: the upper level employs a simplified Practical Byzantine Fault Tolerance (PBFT) protocol to help nodes reach a consensus on data integrity audits. At the lower level, nodes are grouped into clusters based on criteria such as accessibility, organized using a block design strategy. This approach reduces unnecessary information exchange during the auditing process. It maximizes parallel processing and strengthens fault tolerance and system resilience. By distributing data, it also reduces the impact of node failures. Our theoretical analyses and empirical evaluations clearly show that BLA reduces communication complexity compared with conventional PBFT protocols. Additionally, when compared with traditional HVT-based schemes, BLA demonstrates better storage efficiency and improved computational performance, making it a viable and effective solution for data integrity auditing in decentralized storage systems.