Systematizing Decentralization and Privacy: Lessons from 15 years of research and deployments

Decentralized systems are a subset of distributed systems where multiple authorities control different components and no authority is fully trusted by all. This implies that any component in a decentralized system is potentially adversarial. We revise fifteen years of research on decentralization and privacy, and provide an overview of key systems. Decentralized designs may lead to gains in privacy, integrity and availability, but there are also inherent trade-offs that require to be better understood to be addressed. We argue that combination of insights from cryptography, distributed systems, and mechanism design will be necessary to build scalable and successful decentralized systems.