Brief Announcement: Grassroots Distributed Systems: Concept, Examples, Implementation and Applications

Author Ehud Shapiro

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Ehud Shapiro
  • Weizmann Institute of Science, Rehovot, Israel


I thank Andy Lewis-Pye, Nimrod Talmon and Oded Naor for their comments on an earlier version of the manuscript and Idit Keidar for pointing me to related work. Ehud Shapiro is the Incumbent of The Harry Weinrebe Professorial Chair of Computer Science and Biology at the Weizmann Institute.

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Ehud Shapiro. Brief Announcement: Grassroots Distributed Systems: Concept, Examples, Implementation and Applications. In 37th International Symposium on Distributed Computing (DISC 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 281, pp. 47:1-47:7, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


Informally, a distributed system is grassroots if it is permissionless and can have autonomous, independently-deployed instances - geographically and over time - that may interoperate voluntarily once interconnected. More formally, in a grassroots system the set of all correct behaviors of a set of agents P is strictly included in the set of the correct behaviors of P when they are embedded within a larger set of agents P' ⊃ P. Grassroots systems are potentially important as they may allow communities to conduct their social, economic, civic, and political lives in the digital realm solely using their members' networked computing devices (e.g., smartphones), free of third-party control, surveillance, manipulation, coercion, or rent seeking (e.g., by global digital platforms such as Facebook or Bitcoin). Client-server/cloud computing systems are not grassroots, and neither are systems designed to have a single global instance (Bitcoin/Ethereum with hardwired seed miners/bootnodes), and systems that rely on a single global data structure (IPFS, DHTs). An example grassroots system would be a serverless smartphone-based social network supporting multiple independently-budding communities that can merge when a member of one community becomes also a member of another. Here, we formalize the notion of grassroots distributed systems; describe a grassroots dissemination protocol for the model of asynchrony and argue its safety, liveness, and being grassroots; extend the implementation to mobile (address-changing) devices that communicate via an unreliable network (e.g. smartphones using UDP); and discuss how grassroots dissemination can realize grassroots social networking and grassroots cryptocurrencies. The mathematical construction employs distributed multiagent transition systems to define the notions of grassroots protocols, to specify the grassroots dissemination protocols, and to prove their correctness. The protocols use the blocklace - a distributed, partially-ordered counterpart of the replicated, totally-ordered blockchain.

Subject Classification

ACM Subject Classification
  • Computer systems organization → Peer-to-peer architectures
  • Networks → Network protocol design
  • Networks → Formal specifications
  • Software and its engineering → Distributed systems organizing principles
  • Grassroots Distributed Systems
  • Dissemination Protocol
  • Multiagent Transition Systems
  • Blocklace
  • Cordial Dissemination


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