IA-CCF: Individual Accountability for Permissioned Ledgers

Alex Shamis; Peter Pietzuch; Miguel Castro; Cédric Fournet; Edward Ashton; Amaury Chamayou; Sylvan Clebsch; Antoine Delignat-Lavaud; Matthew Kerner; Julien Maffre; Manuel Costa; Mark Russinovich

arXiv · 2105.13116

IA-CCF: Individual Accountability for Permissioned Ledgers

Alex Shamis·Peter Pietzuch·Miguel Castro·Cédric Fournet·Edward Ashton·Amaury Chamayou·Sylvan Clebsch·Antoine Delignat-Lavaud·Matthew Kerner·Julien Maffre·Manuel Costa·Mark Russinovich

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Abstract

Permissioned ledger systems allow a consortium of members that do not trust one another to execute transactions safely on a set of replicas. Such systems typically use Byzantine fault tolerance (BFT) protocols to distribute trust, which only ensures safety when fewer than 1/3 of the replicas misbehave. Providing guarantees beyond this threshold is a challenge: current systems assume that the ledger is corrupt and fail to identify misbehaving replicas or hold the members that operate them accountable -- instead all members share the blame. We describe IA-CCF, a new permissioned ledger system that provides individual accountability. It can assign blame to the individual members that operate misbehaving replicas regardless of the number of misbehaving replicas or members. IA-CCF achieves this by signing and logging BFT protocol messages in the ledger, and by using Merkle trees to provide clients with succinct, universally-verifiable receipts as evidence of successful transaction execution. Anyone can audit the ledger against a set of receipts to discover inconsistencies and identify replicas that signed contradictory statements. IA-CCF also supports changes to consortium membership and replicas by tracking signing keys using a sub-ledger of governance transactions. IA-CCF provides strong disincentives to misbehavior with low overhead: it executes 47,000 tx/s while providing clients with receipts in two network round trips.

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Alex Shamis, Peter Pietzuch, Miguel Castro, Cédric Fournet, Edward Ashton, Amaury Chamayou, Sylvan Clebsch, Antoine Delignat-Lavaud, Matthew Kerner, Julien Maffre, Manuel Costa, Mark Russinovich. 2021-05-27. IA-CCF: Individual Accountability for Permissioned Ledgers. https://arxiv.org/abs/2105.13116

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