A Hierarchical Key Management Scheme for Cross-Domain Secure Deduplication

Convergent encryption has been widely used in secure deduplication technology, but because the data itself is predictable, directly using the hash value of the data as a key is vulnerable to brute force attacks. To this end, researchers have proposed some more secure key management methods. However, they have limited scope of application and poor performance. Therefore, this paper proposes a hierarchical key management scheme based on threshold blind signature. The convergence key generated by multiple key servers ensures the key’s confidentiality, and it effectively avoid the threat of brute force attacks. Moreover, key servers are divided into master key nodes and sub-key nodes, which can reduce the interaction between key servers and improve the efficiency of system initialization. This architecture enables sub-key nodes to be distributed in multiple independent network domains and interact with master key nodes through the Internet. On the one hand, it supports to cross-domain deduplication, and on the other hand, it makes the sub-key node closer to the end user, reducing communication delay for improving key generation efficiency. The experimental results show that the proposed scheme has a greater performance improvement in system initialization and key generation than the fully distributed key management scheme.