Practical Key Management for Searchable Symmetric Encryption Using Fuzzy Extractor

With the spread of cloud computing, information leakage from the cloud is recognized as one of the significant issues. Searchable symmetric encryption has been expected to be a core technology that fundamentally solves this problem. On the other hand, the technology has the security advantage of protecting data in the cloud, instead of the users being responsible for strictly controlling their secret keys. Computer environments and IT literacy vary from user to user, therefore it is important to note that users may be exposed to the risk of attackers gaining unauthorized access to their secret keys. This background underlines the importance of user's key management. In this paper, we propose a method that secures and simplifies this process by encrypting and storing the secret key of SSE using a fuzzy extractor. This method not only enhances the security of SSE but also offers significant benefits for end users, such as the ability to operate in multiple computer environments, thereby providing a more flexible and user-friendly experience. We implemented the proposed method on a laptop computer running Windows 10 and a smartphone running Android OS, which are the users' typical execution environments. As a result, we confirmed that the proposal performs practical application.