The invention belongs to the technical field of
cloud computing, and discloses a cross-domain
authentication and fair audit duplicate removal
cloud storage system based on a block chain. The
system comprises a cross-domain
authentication module, a data
encryption module, a
ciphertext duplicate removal module, an integrity audit module and a
server punishment module. In the
authentication module, acloud user generates a
certificate at a
client in a self-signed mode, the
certificate is stored in a block
chain network after being verified by an
authentication server, the user is verified to compare information such as the
certificate and a block, and whether the certificate is valid or not is verified. According to the method, the problem of hierarchical query
verification of a traditional PKI structure is avoided, the authentication frequency is greatly reduced, and the
verification cost is reduced; By using an intelligent contract, a malicious
server is punished to receive certain penalties and compensate users with impaired benefits under the condition that user data is damaged; And in the duplicate removal module, a data duplicate removal function is realized by using a convergence
encryption technology, so that the
cloud server is prevented from storing too much duplicate data, and the user and the
cloud server are prevented from consuming a large amount of calculation expenditure and storage expenditure.