Secure cloud storage system based on symmetric key

The invention discloses a safety cloud storage system based on a symmetric key, relates to the technical field of cloud storage safety, and adopts the specific scheme that the safety cloud storage system comprises a cloud, a trusted key generation center, a data owner and a data user. The trusted key generation center generates a key; and the data owner allocates the secret key to the data owner and the data user through the secure channel, the data owner outsources the data block and the label thereof and stores the data block and the label thereof in the cloud, the data owner generates a data integrity auditing demand, the cloud uses the selected data block and the label to generate an integrity certificate, and the data user verifies the certificate and returns a verification result. The invention provides a safety cloud storage system based on a symmetric key. For a 3MB data file, the time of an outsourcing step can be controlled to be less than 1 second, and the efficiency of other stages of cloud storag