Multi user multi keyword searchable encryption scheme supporting user authorization

In the big data environment of cloud computing, searchable encryption enables users to selectively access ciphertext data while improving data security. The existing multi-keyword-based encryption schemes have great shortcomings in terms of too large trapdoors and not supporting dynamic authorization of multiple users. Based on this, this paper proposes a multi-user multi-keyword searchable encryption scheme that supports user authorization. This solution supports the data owner to authorize users who access the data, and realizes that the authorized user sends the request for accessing the data to the data owner. Finally, the data owner generates a trapdoor and sends it to the server, and the server sends the result to the user after retrieval. In addition, this solution supports multi-users to dynamically add or withdraw users to ensure data security. This scheme proves that IND-CKA is safe and has the security of keyword trapdoor.