Efficient Verifiable Multi-user Searchable Symmetric Encryption for Encrypted Data in the Cloud

Encryption is the basic technology to ensure the security of the data in the cloud, while ciphertext search is the key to improve the usability of the cloud storage. Most of the searchable encryption schemes consider the honest-but-curious or semi-honest cloud server. However, cloud storage in reality may be unreliable or even malicious. In this case, the encrypted data and search results returned by the server is not completely trustable, so it is crucial to verify the integrity of search results and encrypted data. Considering the untrusted cloud server security model, this paper proposes an efficient verifiable multi-user searchable symmetric encryption (VMSSE) scheme. It is efficient both in computation and storage. In particular, the work performed by the server per returned document is constant as opposed to linear in the size of the data. The computation and storage at the user is O(1). It allows the user to verify the search was computed honestly in the presence of a dishonest-and-curious server. And it supports multi-user searching. Finally, the security analysis shows that it is an efficient and feasible scheme.