Large File Security Outsourcing and Sharing Method Based on Blockchain.

With the development of the big data era, the amount of data has entered an explosive growth phase. Limited by the constraints of cost, efficiency, and security of self-built storage systems, enterprises are forced to outsource files to cloud storage systems. However, the lack of file security and auditability in cloud storage systems continues to threaten the security of outsourced files. This paper designs and implements a large file security outsourcing and sharing method based on blockchain (BFSOut). It uses Hyperledger Fabric and Interplanetary File System (IPFS) as the underlying storage engine, which solves the problem of cloud storage security issues. In order to ensure the security of outsource files, the client-side offline encryption and decryption is used. Furthermore, a dynamic hybrid encryption scheme is adopted, making the overall encryption effect more efficient. Meanwhile, BFSOut effectively reduces the time consumption of large file encryption and decryption by 20%–30% through the parallel block encryption and decryption model. Experimental performance and security analysis show that the method has good performance and safety. [ABSTRACT FROM AUTHOR]