Toward Privacy-Preserving Shared Storage in Untrusted Blockchain P2P Networks

The shared storage is essential in the decentralized system. A straightforward storage model with guaranteed privacy protection on the peer-to-peer network is a challenge in the blockchain technology. The decentralized storage system should provide the privacy for the parties since it contains numerous data that are sensitive and dangerous if misused by maliciously. In this paper, we present a model for shared storage on a blockchain network which allows the authorized parties to access the data on storage without having to reveal their identity. Ring signatures combined with several protocols are implemented to disguise the signer identity thereby the observer is unlikely to determine the identity of the parties. We apply our proposed scheme in the healthcare domain, namely, decentralized personal health information (PHI). In addition, we present a dilemma to improve performance in a decentralized system.