Achieving Secure Dynamic Searchable Symmetric Encryption for Data Sharing Services via Blockchain

In the era of big data, massive data is generated. The use of a large amount of data has brought great convenience to people's lives and promoted the improvement of production efficiency. However, independent organizations in various fields have their own information systems. The incompatible systems and the lack of trust among organizations lead to data silos, which seriously hinders data sharing and usage. In order to break data barriers and increase the reliability and security of data sharing, we construct a blockchain-based dynamic searchable symmetric encryption scheme for multiusers. Blockchain, serving as a retrieval platform, uses a bit matrix to store the correspondence between keywords and data owners who just upload encrypted keywords rather than all original files to blockchain. At the same time, we verify user identity through random numbers, which not only realizes access control, but also ensures forward security. We tested the performance of the scheme locally. The results show that the encryption, authorization and revocation and query performance of this scheme are good.