Securing People and their Machines Against Major Faults

2026-07-02

AI Summary

This work addresses the critical challenge of irrecoverable identity and state loss in decentralized grassroots platforms due to private key or device compromise. It introduces the first fault-tolerant recovery framework that leverages user-curated social graphs and employs designated identity and state custodians. By decoupling identity from state recovery and modeling both as multi-agent atomic transactions, the system enables secure key rotation and state restoration through majority consensus among custodians—without reliance on global infrastructure. Built upon a voluntary communication agent architecture and an eventually synchronous message-passing model, the framework guarantees that under recoverable failures, executions map to canonical ones. Sovereign monetary integrity is preserved via precisely recoverable single-write logs that prevent double-spending.

Abstract

We consider grassroots platforms -- distributed systems of agents consisting of people identified by self-chosen public keys and their machines (smartphones) -- and wish to make them secure against \emph{major faults}: the loss of their private keys and/or their smartphones. As grassroots platforms have no global resource to rely on for recovery, our peer-based solution is based on: (\ia) \emph{a grassroots social graph} in which agents establish and maintain friendships; (\ib) \emph{identity custodians}, designated by each person, and (\ic) \emph{state custodians}, which are grassroots platform-specific. Upon a person experiencing identity loss, and given a willing supermajority of the identity custodians of the person, the friends of the person replace the old public key with the new one across the graph and restore friendships, where all friends serve as state custodians for the social graph. Choosing a new keypair, obtaining a new smartphone, and convincing identity custodians to will a change of key all happen ``off-chain''. Recovery from machine loss without loss of key (e.g. smartphone run over by truck, or its memory wiped) is simpler, requiring only the help of state custodians. We specify the social graph and its secure version as guarded multiagent atomic transactions, and implement the secure social graph via communicating volitional agents, an eventually synchronous message-passing model one step closer to implementation. We prove the implementation maps runs with recoverable faults to correct runs of the specification. We follow a similar path for grassroots coins and bonds, showing a common core as well as the platform-specific aspects of state recovery: a currency's single-writer log is recovered exactly, the recovered sovereign resuming without double-spending.

Problem

• grassroots platforms
• major faults
• private key loss
• smartphone loss
• secure recovery

Innovation

• grassroots platforms
• identity recovery
• social graph
• custodians
• fault tolerance