Lightweight (k, n)-file sharing scheme for distributed storages with diverse communication capacities

Since the novel ideas on secret sharing were first proposed in 1979, a number of variants have been invented, based on these two schemes. The secret sharing schemes have selectively been applied to many distributed storage systems connected by both wired and wireless communication links for securely storing files. However, when gathering file fragments necessary to recover a file from network-based distributed storages with diverse communication capacities, a link with the slowest communication capability can be a significant bottleneck in overall performance. Furthermore, in applying the existing schemes directly to the distributed storage systems, there occurs a critical limitation, that of requiring substantial computational overhead to divide a file into fragments and recover a file from them. We propose a new lightweight (k, n)-file sharing scheme for the distributed storages with diverse capacities, where n is the number of file fragments, and k is the minimum number of fragments needed to recover a file. Contrary to the previous works, our scheme can adaptively schedule size of the stored file fragments, and the amount of transmission data in downloading file fragments by considering the communication status of each storage device, minimizing the effect of bottleneck links, and thus reducing the file recovery time. In addition, our scheme significantly reduces the computational complexity by adopting a pure combinatorial method which does not require the solution of computation-intensive polynomial equations. We demonstrate that our scheme can greatly decrease both computation and communication costs, compared to the previous secret sharing schemes for the distributed storages.