BOSS: A Blockchain Off-State Sharing System

TL;DR

BOSS is a blockchain system that enables secure sharing of large off-chain data files with controlled access and reliable custody, using encryption and transaction-based key management.

Contribution

It introduces an off-state sharing protocol for blockchain systems to handle big data files securely and efficiently, with a prototype implementation on Hyperledger Fabric.

Findings

Feasibility of off-state data sharing demonstrated

Secure cryptographic key management validated

Performance metrics show practical viability

Abstract

Blockchain has been applied to data sharing to ensure the integrity of data and chain of custody. Sharing big data such as large biomedical data files is a challenge to blockchain systems since the ledger is not designed to maintain big files, access control is an issue, and users may be dishonest. We call big data such as big files stored outside of a ledger that includes the blockchain and world state at a blockchain node as "off-state" and propose an off-state sharing protocol for a blockchain system to share big data between pairs of nodes. In our protocol, only encrypted files are transferred. The cryptographic key is stored in the world state in a secure way and can be accessed only by authorized parties. A receiver has to request the corresponding cryptographic key from the sender to decrypt such encrypted files. All requests are run through transactions to establish reliable chain of custody. We design and implement a prototypical blockchain off-state sharing system, BOSS, with Hyperledger Fabric. Extensive experiments were performed to validate the feasibility and performance of BOSS.