Dynamic Ciphertext Retrieval Scheme with Two-Way Verification

The dynamic searchable encryption technology realizes the dynamic update of data, which can cope with more flexible application challenges, but the problem of privacy leakage and the dishonesty between users and cloud servers during data update have not been solved. In order to solve the above problem, a dynamic ciphertext retrieval scheme with two-way verification is proposed to achieve two-way verification between users and cloud servers. First, the introduction of bitmap index and homomorphic addition symmetric encryption technology, the use of bitmap index can represent all document identifiers involved in each update of a single keyword, reduce the number of cloud server searches and local index encryption times, thereby improve search and update efficiency, and the use of homomorphic addition symmetric encryption to encrypt the bitmap index can effectively protect the safe update of data. Secondly, the clients upload the aggregate MACs to the blockchain, and use the blockchain to verify the correctness of the results returned by the cloud server to prevent fraudulent behaviors between users and the cloud servers. Finally, the experimental results and security analysis show that the solution meets forward security and backward security, and improves efficiency in index building, search, update, and verification.