The invention discloses a secret key updating method for 
cloud storage and an implementation method of a 
cloud data auditing 
system, and belongs to the technical field of 
network security. The secret key updating method for 
cloud storage comprises the steps that when a 
cloud user needs to update a secret key, a CA 
server is requested to generate a new secret key, and a new file 
label and a new data block 
label are generated based on a file 
label and a data block label downloaded from a 
cloud server, the old secret key and the new secret key at present, are uploaded to the 
cloud server, and are used for replacing the corresponding old file label and the corresponding old data block label in the 
cloud server. Meanwhile, the invention further discloses the implementation method of the 
cloud data auditing 
system on the basis of zero-knowledge 
verification. When the 
cloud user needs to update the secret key, the corresponding file label and the corresponding data block label on the cloud 
server are updated based on the secret key updating method for 
cloud storage. The secret key updating method for cloud storage and the implementation method of the 
cloud data auditing 
system are used in a cloud network, the communication cost, caused by changing of the secret key, between the cloud 
server and the 
cloud user can be remarkably reduced, the calculation cost of the operation that the cloud user calculates the labels again is reduced, and the data privacy can be effectively protected in the auditing process.