In cloud storage, public auditing is a more popular data integrity verification technique since it allows users to delegate auditing tasks to a fully trusted third-party auditor (TPA). However, it is difficult to find such a TPA in practical application. Besides, the centralised auditing model makes TPA have to bear burdensome work pressure, which limits the practicability of existing schemes. In this paper, we firstly proposed a blockchain-based generalised shared auditing mechanism BCSA in the cross-user scenario, which aims at achieving available public auditing with a non-fully trusted TPA, and reducing the user's auditing fees and TPA's work pressure by allowing data users to share their auditing procedure with others. Furthermore, we initialise a concrete construction BCSAD with Diffie–Hellman protocol for the cross-user auditing scenario with different data. Likewise, we also propose a novel construction BCSAI for the cross-user auditing scenario with identical data, which utilises a password-authenticated key exchange (PAKE) protocol to achieve shared auditing and ciphertext deduplication, reducing data storage and auditing fees for data users and alleviating service pressure on the cloud server and TPA. Security and performance analysis evaluate the practicability of the proposed scheme.

在云存储中，公共审计是一种更流行的数据完整性验证技术，因为它允许用户将审计任务委托给完全信任的第三方审计 (TPA)。然而，在实际应用中很难找到这样的TPA。此外，集中审计模式使得TPA不得不承受繁重的工作压力，限制了现有方案的实用性。在本文中，我们首次在跨用户场景下提出了一种基于区块链的通用共享审计机制BCSA，旨在通过非完全信任的TPA实现公开审计，通过允许TPA降低用户的审计费用和TPA的工作压力。数据用户与他人分享他们的审计程序。此外，我们使用 Diffie-Hellman 协议初始化了一个具体的构造 BCSAD，用于具有不同数据的跨用户审计场景。同样，我们还针对数据相同的跨用户审计场景提出了一种新的构建BCSAI，它利用密码认证密钥交换（PAKE）协议实现共享审计和密文去重，减少数据用户的数据存储和审计费用，缓解云服务器和TPA的服务压力。安全性和性能分析评估了所提出方案的实用性。减少数据用户的数据存储和审计费用，减轻云服务器和TPA的服务压力。安全性和性能分析评估了所提出方案的实用性。减少数据用户的数据存储和审计费用，减轻云服务器和TPA的服务压力。安全性和性能分析评估了所提出方案的实用性。