File sharing method and device based on block chain cloud storage

The invention can be applied to the technical field of application of a block chain technology in the financial aspect, and provides a file sharing method and device based on block chain cloud storage. The block chain cloud storage-based file sharing method applied to a shared file providing block chain node comprises the following steps: generating an identifier CID of a shared file according to the content of the shared file; encrypting the shared file according to the identifier CID and an identity ID corresponding to a shared file receiving block chain node, and generating an attribute secret key and a private key corresponding to the shared file receiving block chain node; and uploading the encrypted shared file and the attribute secret key and the private key to the block chain. According to the method, flexible file sharing among users based on block chain cloud storage can be realized, the users only need to record one memory key to complete sharing and acquisition of the shared file, and meanwhile, d