DSSE-DMVS: A blockchain-based dynamic searchable symmetric encryption supporting multi-keyword queries and data deduplication

Dynamic Searchable Symmetric Encryption (DSSE) allows users to search for encrypted data and supports dynamic updating of data. In recent years, DSSE has become a research hotspot because it can address privacy and security issues when storing and retrieving encrypted data in cloud environments. However, most of the existing DSSE schemes suffer from inefficiencies in updating data and do not take into account data redundancy due to users misuse. These schemes only support the verification of search result and lack mechanisms to penalize malicious servers as well as ensure fairness to users. To address these issues, we design a blockchain-based dynamic searchable symmetric encryption scheme called DSSE-DMVS. Firstly, we adopt the bitmap as the index data structure to efficiently implement multi-keyword queries and index updates through logical operators AND and XOR. Then, we introduce a data deduplication mechanism to enhance retrieval efficiency and reduce the waste of cloud storage resources. To further penalize malicious servers and ensure fairness for users, we store the actual encrypted files and indexes on the server and blockchain, respectively. Additionally, we use the smart contract to manage the monetary rewards. Formalized safety analysis and experimental results show that DSSE-DMVS is safe and effective in practical applications.