Block Design-Based Key Agreement for Group Data Sharing in Cloud Computing

TLDR

Data sharing in cloud computing improves efficiency, yet securing group data sharing and enabling efficient group access remain major challenges, making key agreement protocols essential. This work proposes a block design‑based key agreement protocol that supports multiple participants in cloud environments. The protocol employs a symmetric balanced incomplete block design to generate a common conference key and allows the participant set to be flexibly extended according to the block structure. It achieves linear computational complexity, reduced communication overhead, and fault tolerance against key attacks comparable to Yi’s protocol.

Abstract

Data sharing in cloud computing enables multiple participants to freely share the group data, which improves the efficiency of work in cooperative environments and has widespread potential applications. However, how to ensure the security of data sharing within a group and how to efficiently share the outsourced data in a group manner are formidable challenges. Note that key agreement protocols have played a very important role in secure and efficient group data sharing in cloud computing. In this paper, by taking advantage of the symmetric balanced incomplete block design (SBIBD), we present a novel block design-based key agreement protocol that supports multiple participants, which can flexibly extend the number of participants in a cloud environment according to the structure of the block design. Based on the proposed group data sharing model, we present general formulas for generating the common conference key IC for multiple participants. Note that by benefiting from the (v, k + 1, 1)-block design, the computational complexity of the proposed protocol linearly increases with the number of participants and the communication complexity is greatly reduced. In addition, the fault tolerance property of our protocol enables the group data sharing in cloud computing to withstand different key attacks, which is similar to Yi's protocol.