Now, it is common for patients and medical institutions to outsource their data to cloud storage. This can greatly reduce the burden of medical information management and storage and improve the efficiency of the entire medical industry. In some cases, the group-based cloud storage system is also very common to be used. For example, in an medical enterprise, the employees outsource the working documents to the cloud storage and share them to the colleagues. However, when the working documents are outsourced to the cloud servers, how to ensure their security is a challenge problem for they are not controlled physically by the data owners. In particular, the integrity of the outsourced data should be guaranteed. And the secure cloud auditing protocol is designed to solve this issue. Recently, a lightweight secure auditing scheme for shared data in cloud storage is proposed. Unfortunately, we find this proposal not secure in this paper. It’s easy for the cloud server to forge the authentication label, and thus they can delete all the outsourced data when the cloud server still provide a correct data possession proof, which invalidates the security of the cloud audit protocol. On the basis of the original security auditing protocol, we provide an improved one for the shared data, roughly analysis its security, and the results show our new protocol is secure.

中文翻译：

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用于共享医疗数据的改进的轻量级云存储审核协议

现在，患者和医疗机构通常将其数据外包给云存储。这样可以大大减轻医疗信息管理和存储的负担，提高整个医疗行业的效率。在某些情况下，基于组的云存储系统也很常见。例如，在一家医疗企业中，员工将工作文档外包到云存储中，并共享给同事。但是，将工作文档外包给云服务器时，如何确保其安全性是一个难题，因为它们不受数据所有者的物理控制。特别是，应确保外包数据的完整性。安全云审核协议旨在解决此问题。最近，提出了一种针对云存储中共享数据的轻量级安全审计方案。不幸的是，我们发现该建议在本文中并不安全。云服务器很容易伪造身份验证标签，因此当云服务器仍提供正确的数据拥有证明时，它们可以删除所有外包数据，这会使云审计协议的安全性失效。在原始安全审计协议的基础上，我们为共享数据提供了一种改进的协议，粗略分析了其安全性，结果表明我们的新协议是安全的。这会使云审核协议的安全性失效。在原始安全审计协议的基础上，我们为共享数据提供了一种改进的协议，粗略分析了其安全性，结果表明我们的新协议是安全的。这会使云审核协议的安全性失效。在原始安全审计协议的基础上，我们为共享数据提供了一种改进的协议，粗略分析了其安全性，结果表明我们的新协议是安全的。