Security enhanced certificateless searchable public key encryption scheme

With the rapid development of cloud computing, how to use cloud server for secure storage of data has become a hot research issue in related fields. The cloud storage system improves the accessibility and availability of stored data while saving local management costs. However, it also risks data privacy leakage and threatens data security. After uploading encrypted files, users will face the problem of how to search the encrypted data effectively in the cloud. Searchable encryption technology can not only efficiently retrieve the data required by visitors, but also ensure the privacy of user information and data security. A certificateless searchable public key encryption scheme with enhanced security is proposed to solve the problems of key verification, certificate management and transaction opacity in traditional searchable encryption schemes. Firstly, the key generation center is introduced to avoid certificate management and key escrow while ensuring search. Secondly, the security of the scheme is enhanced on the basis of effective ciphertext search. Smart contracts ensure traceability and transparency of transactions between data users and data owners. Finally, it is proved that the scheme can resist the offline keyword guessing attack under the random prediction model. Compared with other certificateless searchable encryption schemes, this scheme combined with smart contract not only improves the security and transaction reliability of the scheme, but also has certain advantages in terms of retrieval time and scheme scalability.