Research on database ciphertext retrieval based on homomorphic encryption

This paper proposes a secure retrieval scheme based on homomorphic encryption for the server-side structured database. With the advantage of this scheme, ciphertext in server under unreliable storage circumstance can be efficiently retrieved without exposition of plaintext. Users can also have detailed access to their data. In this paper, a data encryption and decryption algorithm based on homomorphic encryption is proposed for character data in database. Server can calculate and operate the ciphertext data directly. An equivalent retrieval algorithm based on homomorphic encryption is proposed for equivalent retrieval of ciphertext data, which can effectively reduce the amount of data returned to the client and improve the retrieval efficiency. A counting joint index generation algorithm with upper limit based on dual encoding function is proposed for fuzzy retrieve of character data which can improve the efficiency of the server's filtering of the irrelevant data and reduce the waste of time and space.