Industrial Internet of Things security data sharing method based on block chain

The invention discloses an industrial Internet of Things secure data sharing method based on a block chain, and the method comprises the steps: firstly, a data owner calculates a hash value of original data, encrypts the original data, uploads the original data to an industrial Internet of Things cloud platform, returns a data address, divides a symmetric key into a plurality of sub-keys, encrypts the sub-keys, and stores the encrypted sub-keys; uploading the encrypted sub-key and metadata to a block chain system, creating an access control smart contract, and deploying the access control smart contract on a block chain; then a data requester calls a request data smart contract and initiates a data request to the block chain system; the block chain system executes an access control smart contract, and returns metadata and a sub-key after the judgment is passed; and finally, the data requester obtains a plurality of sub-keys, recovers a decryption key, requests encrypted data from the industrial Internet of Th