Many commercial cloud service providers (CSPs) adopt pay-per-query pricing models, in which data owners are charged based on the amount of data scanned by each query. In such a data sharing model, not only the privacy preservation for the data and queries but also the trustworthiness of the underlying billing system is of the utmost importance. In this paper, we revisit multi-key searchable encryption (MKSE), an efficient and secure data search algorithm allowing a data owner to grant users the ability to retrieve data of interest over the outsourced, encrypted datasets. We first investigate which factor in existing MKSE schemes renders authorized users over-privileged such that, without risking their credits (e.g., leaking the private keys and/or the passwords for their accounts associated with a project where the shared data resides), they can allow unauthorized users to make valid queries. Unfortunately, this concern may be devastating because the queries made by unauthorized users would incur unexpected financial damage to the owner in practical pay-per-query models. We then propose a novel multi-key data search scheme that is resilient to unauthorized queries. The proposed scheme features a novel user authorization mechanism that carefully limits user privilege such that even an authorized user cannot illegally invite unauthorized users to query unless he entirely leaks his credit. We demonstrate the proposed scheme is comparable to prior work in terms of performance while achieving a higher level of security.

中文翻译：

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通过安全按查询付费的加密存储上的多密钥相似数据搜索


许多商业云服务提供商（CSP）采用按查询付费的定价模式，其中数据所有者根据每次查询扫描的数据量付费。在这样的数据共享模型中，不仅数据和查询的隐私保护，而且底层计费系统的可信度也至关重要。在本文中，我们重新审视多密钥可搜索加密（MKSE），这是一种高效且安全的数据搜索算法，允许数据所有者授予用户通过外包加密数据集检索感兴趣数据的能力。我们首先调查现有 MKSE 方案中的哪些因素使授权用户拥有过多的特权，这样，在不冒信用风险（例如，泄露与共享数据所在项目相关的帐户的私钥和/或密码）的情况下，他们可以允许未经授权的用户进行有效的查询。不幸的是，这种担忧可能是毁灭性的，因为在实际的按查询付费模式中，未经授权的用户进行的查询会给所有者带来意想不到的经济损失。然后，我们提出了一种新颖的多键数据搜索方案，该方案能够适应未经授权的查询。所提出的方案具有新颖的用户授权机制，该机制仔细地限制用户权限，使得即使授权用户也不能非法邀请未经授权的用户查询，除非他完全泄露自己的信用。我们证明所提出的方案在性能方面与之前的工作相当，同时实现了更高级别的安全性。