Securing People and their Machines Against Major Faults

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.

• The paper presents recovery protocols that enable users to restore digital identity and machine state on grassroots platforms by leveraging trusted custodians and social graphs.
• It employs volitional multiagent atomic transactions to ensure secure, consensus-based key replacement and state recovery even after major faults.
• The study demonstrates improved fault tolerance and decentralized resiliency without relying on central authorities, advancing security in egalitarian networks.

Securing People and Their Machines Against Major Faults

Introduction

The paper "Securing People and their Machines Against Major Faults" addresses the problem of maintaining security and continuity in grassroots platforms in the event of a major fault. A grassroots platform is characterized as a decentralized system operated by individuals through personal devices, such as smartphones, without reliance on a central authority. This work discusses strategies to recover from major faults, specifically focusing on identity and machine state recovery.

Grassroots Platforms and Major Faults

Grassroots platforms operate independently and are free from autocratic or plutocratic influence, presenting themselves as egalitarian alternatives to centralized and decentralized mainstream digital infrastructures. These platforms, like grassroots social networks and coins, rely on a peer-to-peer architecture where user identities are tied to cryptographic keys. A major fault, such as the loss of a private key or a smartphone, poses a significant risk to the integrity and usability of these platforms since they lack centralized recovery paths.

Secure Recovery Mechanisms

The proposed recovery mechanisms involve a combination of social graphs, identity custodians, and state custodians. The social graph forms the underlying connectivity structure maintained through volitional multiagent atomic transactions. Users designate trusted identity custodians who aid in recovering identity by authorizing a key change through consensus. State custodians, usually friends within the social graph, assist in restoring the platform-specific state if a machine is lost but the key remains intact.

1. Identity Loss Recovery: Upon the loss of a key, users generate a new key pair offline, solicit support from identity custodians, and facilitate key replacement across the network. A supermajority of custodians must authorize this action.
2. Machine State Recovery: If a machine is lost but the key remains secure, the user can reconstruct their network presence with the assistance of friends through transactions in the social graph, requiring no additional authorization.

Implementation and Fault Tolerance

The paper describes implementing these recovery protocols using volitional multiagent atomic transactions, focusing on ensuring that every transaction is guarded by agents who must express willingness. This peer-based method maintains mutual trust and operational correctness even under failure circumstances. The paper's theoretical contribution includes modeling friendships and transactions within a secure, decentralized system.

Implications and Future Work

The research highlights a robust architecture ensuring platform security without needing centralized oversight. The implications of this approach are significant for enhancing resilience and privacy in decentralized networks. Future developments could expand to other application domains or integrate with existing decentralized finance systems, fostering more resilient economic systems against cyber threats or user-level malfunctions.

Conclusion

"Securing People and Their Machines Against Major Faults" presents a viable solution to operational continuity in grassroots platforms through peer-based recovery mechanisms. It underscores the potential for secure, decentralized systems to withstand major faults without relying on centralized interventions, highlighting significant progress in distributed computing and social network resilience methodologies.