Fault-Tolerant Based Group Key Servers with Enhancement of Utilizing the Contributory Server for Cloud Storage Applications

Abstract

Group key management in cloud computing has become a trending topic in recent decades. This paper deals with the implementation of clustered structure based on centralized key management. In a centralized key management scheme, the Key Server is responsible for generating user keys and group keys of the cloud. The proposed work consists of a single Central Server and a number of sub-servers and each sub-server can manage multiple different groups. To achieve fault tolerance, each group is replicated into multiple different sub-servers. Users are allocated to a specific group and the size of the group is limited. Each group has a separate group key to avoid internal attacks and they can communicate through a central server. The proposed work encourages intergroup communication and essentially reduces the computations and storage complexity of the central server. Also, we propose to remove the rekeying process upon a new user joining by maintaining a file access list for each file, which will reduce the impact of the security features that even there is a leakage of the group key after the user leaves. Further, this paper proposes a contributory key management scheme where each member of the group is responsible for generating the group key.