IA-CCF: Individual Accountability for Permissioned Ledgers

Authors: 

Alex Shamis and Peter Pietzuch, Microsoft Research and Imperial College London; Burcu Canakci, Cornell University; Miguel Castro, Cédric Fournet, Edward Ashton, Amaury Chamayou, Sylvan Clebsch, and Antoine Delignat-Lavaud, Microsoft Research; Matthew Kerner, Microsoft Azure; Julien Maffre, Olga Vrousgou, Christoph M. Wintersteiger, and Manuel Costa, Microsoft Research; Mark Russinovich, Microsoft Azure

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.

NSDI '22 Open Access Sponsored by
King Abdullah University of Science and Technology (KAUST)

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BibTeX
@inproceedings {278332,
author = {Alex Shamis and Peter Pietzuch and Burcu Canakci and Miguel Castro and Cedric Fournet and Edward Ashton and Amaury Chamayou and Sylvan Clebsch and Antoine Delignat-Lavaud and Matthew Kerner and Julien Maffre and Olga Vrousgou and Christoph M. Wintersteiger and Manuel Costa and Mark Russinovich},
title = {{IA-CCF}: Individual Accountability for Permissioned Ledgers},
booktitle = {19th USENIX Symposium on Networked Systems Design and Implementation (NSDI 22)},
year = {2022},
isbn = {978-1-939133-27-4},
address = {Renton, WA},
pages = {467--491},
url = {https://www.usenix.org/conference/nsdi22/presentation/shamis},
publisher = {USENIX Association},
month = apr,
}

Presentation Video