Abstract:

Current information systems face security risks such as log data being easily tampered, forged and deleted, as well as unauthorized access to data. The existing research methods of log storage and access mostly use searchable encryption technology. Although the encrypted storage of sensitive log data is realized, there is a lack of research on the fairness of the ciphertext retrieval process and the control of ciphertext access rights. Aiming at the above research problems, this paper designed a method for secure storage and fair access of logs based on smart contracts. As a participant in the searchable encryption process, the smart contract performed the comparison of search trapdoors and the verification of ciphertext search results, so that the correctness of ciphertext search process could be verified without a third-party entity. At the same time, the deposit mechanism was used to ensure fair payment between data users and cloud storage servers during the search process. In this method, the role-based access control policy was embedded in the searchable encryption process. Through the one-to-many mapping between the role public key and the entity identity public key, the searchable encryption was extended to the many-to-many mode, and the authorized access of the log ciphertext data was realized. Experiments and analyses show that this method can meet the requirements of integrity and confidentiality of log data storage, ensure fairness and correctness of ciphertext retrieval process through smart contract and deposit mechanism, and avoid unauthorized access of data through role-based access control.

Key words: smart contract, searchable encryption, secure storage, fair payment, access control