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Ouroboros AutoSyn: Time Based Permissionless Synchrony Model for PoS

Joshua Shen

TL;DR

Ouroboros AutoSyn addresses the challenge of decentralized clock synchronization in permissionless PoS by replacing a central round-status clock with a real-time global clock $G_{AutoClock}$ and time-based rounds with epoch-driven adjustments. The protocol enables dynamic participation through registration/join/leave procedures, resynchronization for new entrants, and an adaptive round length $t_{round}$ that responds to network conditions via the adjustment procedure. It provides formal security guarantees (CP, CG, CQ) under probabilistic delivery with delivery ratio $\eta$, and extends these guarantees to dynamic network settings with a UC-realizable ledger interface $G_{LEDGER}$ through a simulator, highlighting the protocol’s practical viability in real-world, asynchronous networks. Overall, AutoSyn advances decentralized PoS by eliminating the need for per-node round tracking while maintaining strong security properties and supporting ad-hoc participation, making PoS more scalable and robust to network delays and churn.

Abstract

Blockchain as a promising technology is gaining its popularity ever since proof-of-work based Bitcoin came to the world. Nevertheless, Bitcoin achieves consensus at an expensive cost of energy. Proof-of-stake is one of the solutions for such a problem. Participants of PoS protocols achieve dynamic-availability in permissionless settings. Parties can join and leave the protocol at their will without notifying others. However, such protocol relies heavily on a central clock, providing the function of synchrony by collecting the finish status of every honest participant. In our protocol, the global function maintains the round information for each participant no longer needed. We analyze and modify the round into real-time based round model. Message delivery delay is also taken into consideration of the round length. However, participant need the connection of a real-world time global clock which is crucial to calculate the current round. And round length also is adjusted due to the changing network situation at the start of every new epoch.

Ouroboros AutoSyn: Time Based Permissionless Synchrony Model for PoS

TL;DR

Ouroboros AutoSyn addresses the challenge of decentralized clock synchronization in permissionless PoS by replacing a central round-status clock with a real-time global clock and time-based rounds with epoch-driven adjustments. The protocol enables dynamic participation through registration/join/leave procedures, resynchronization for new entrants, and an adaptive round length that responds to network conditions via the adjustment procedure. It provides formal security guarantees (CP, CG, CQ) under probabilistic delivery with delivery ratio , and extends these guarantees to dynamic network settings with a UC-realizable ledger interface through a simulator, highlighting the protocol’s practical viability in real-world, asynchronous networks. Overall, AutoSyn advances decentralized PoS by eliminating the need for per-node round tracking while maintaining strong security properties and supporting ad-hoc participation, making PoS more scalable and robust to network delays and churn.

Abstract

Blockchain as a promising technology is gaining its popularity ever since proof-of-work based Bitcoin came to the world. Nevertheless, Bitcoin achieves consensus at an expensive cost of energy. Proof-of-stake is one of the solutions for such a problem. Participants of PoS protocols achieve dynamic-availability in permissionless settings. Parties can join and leave the protocol at their will without notifying others. However, such protocol relies heavily on a central clock, providing the function of synchrony by collecting the finish status of every honest participant. In our protocol, the global function maintains the round information for each participant no longer needed. We analyze and modify the round into real-time based round model. Message delivery delay is also taken into consideration of the round length. However, participant need the connection of a real-world time global clock which is crucial to calculate the current round. And round length also is adjusted due to the changing network situation at the start of every new epoch.
Paper Structure (49 sections, 46 equations, 5 figures, 2 tables)

This paper contains 49 sections, 46 equations, 5 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Our Model
  3. The New Protocol: Ouroboros AutoSyn
  4. Overview and Main Challenges
  5. Party Types
  6. Technical Overview with Differences to Ouroboros Genesis
  7. Time-based round structure
  8. Registration and Special Procedures
  9. Mode of Operation for Alert Parties
  10. Further Ledger Queries
  11. De-Registration and Re-Joining
  12. The Adjusting Round Procedure of Ouroboros AutoSyn
  13. The Resynchronization Procedure of Ouroboros AutoSyn
  14. Security Analysis
  15. Time structure of a round
  16. ...and 34 more sections

Figures (5)

  • Figure 1: Timing diagram showing message delivery between four processes across four time slots, generating $B_{1}$-$B_{2}$-$B_{4}$
  • Figure 2: Timing diagram showing message delivery between four processes across four time slots, generating $B_{1}$-$B_{2}^{\prime}$-$B_{4}$
  • Figure 3: Example timeline diagram showing two processes P1 and P2 with slot segments
  • Figure 4: Timeline diagram showing interaction between P1 and P2 across two time slots
  • Figure 5: Timeline diagram showing interaction between P1 and P2 across two time slots