SPIDE: sybil-proof, incentivized data exchange

Abstract

Decentralized, open-access blockchain systems opened up new, exciting possibilities—all without reliance on trusted third parties. Regardless of the employed consensus protocol, the overall security, decentralization and effectiveness of such systems, largely depend upon properly structured incentives. Indeed, as has been previously spotted by Babaiaff et al. Bitcoin-like systems, oftentimes lack some of these. Specifically, current blockchain-systems fail to incentivize one of their crucial aspects–the underlying data exchange. As we rationalize, proper incentivization of that layer could lead to lower transactions’ confirmation-times, improved finalization guarantees and at the same time to discouragement of malicious behaviours such as block-withholding attacks. Indeed, incentivization of the data-exchange layer allows the system to remain operational when all agents, including routing nodes, are assumed to be rational. In this work, while focusing on the problem of sybil-proof data exchange, we revisit previous approaches, showcasing their shortcomings and lay forward the first information exchange framework; with integrated routing and reward-function mechanics, provably secure in thwarting Sybil-nodes in 1-connected or eclipsed networks. The framework neither requires nor assumes any kind of constraints in regard to the network’s topology (i.e. the network is modelled as a random-connected graph) and rewards information propagators through a system-intrinsic virtual asset maintained by the decentralized state-machine. The proposal, while being storage and transmission efficient is suitable for rewarding not only consensus-related datagrams (both data-blocks and transactions) but consensus-extrinsic information as well, thus facilitating an universal sybil-proof data-exchange apparatus, provably valid under the assumption of existence of a data store whose property of non-malleability emerges as time approaches infinity. Our research was conducted under two scenarios—with round leader known and unknown in advance of each transactional round.