Brief Announcement: Auditable Register Emulations

Authors Vinicius Vielmo Cogo , Alysson Bessani

Thumbnail PDF


  • Filesize: 0.59 MB
  • 4 pages

Document Identifiers

Author Details

Vinicius Vielmo Cogo
  • LASIGE, Faculdade de Ciências, University of Lisbon, PT
Alysson Bessani
  • LASIGE, Faculdade de Ciências, University of Lisbon, PT

Cite AsGet BibTex

Vinicius Vielmo Cogo and Alysson Bessani. Brief Announcement: Auditable Register Emulations. In 35th International Symposium on Distributed Computing (DISC 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 209, pp. 53:1-53:4, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


We initiate the study of auditable storage emulations, which provide the capability for an auditor to report the previously executed reads in a register. We define the notion of auditable register and its properties, and establish tight bounds and impossibility results for auditable storage emulations in the presence of faulty base storage objects. Our formulation considers registers that securely store data using information dispersal (each base object stores only a block of the written value) and supporting fast reads (that complete in one communication round-trip). In such a scenario, given a maximum number f of faulty storage objects and a minimum number τ of data blocks required to recover a stored value, we prove that (R1) auditability is impossible if τ ≤ 2f; (R2) implementing a weak form of auditability requires τ ≥ 3f+1; and (R3) a stronger form of auditability is impossible. We also show that (R4) signing read requests generically overcomes the lower bound of weak auditability, while (R5 and R6) totally ordering operations or using non-fast reads enables strong auditability. These results establish that practical storage emulations need f to 2f additional objects compared to their original lower bounds to support auditability.

Subject Classification

ACM Subject Classification
  • Computing methodologies → Distributed algorithms
  • Computer systems organization → Reliability
  • Security and privacy → Information accountability and usage control
  • Applied computing → Evidence collection, storage and analysis
  • Auditability
  • Secure Storage
  • Information Dispersal


  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    PDF Downloads


  1. Soumya Basu, Alin Tomescu, Ittai Abraham, Dahlia Malkhi, Michael K. Reiter, and Emin Gün Sirer. Efficient verifiable secret sharing with share recovery in BFT protocols. In Proc. of the 26th ACM Conference on Computer and Communications Security (CCS), page 2387–2402, 2019. URL:
  2. Alysson Bessani, Miguel Correia, Bruno Quaresma, Fernando Andre, and Paulo Sousa. DepSky: Dependable and secure storage in cloud-of-clouds. ACM Transactions on Storage (TOS), 9(4):12:1-12:33, 2013. URL:
  3. Vinicius Vielmo Cogo and Alysson Bessani. Auditable register emulations. CoRR, abs/1905.08637, 2019. URL:
  4. Rachid Guerraoui and Marko Vukolić. How fast can a very robust read be? In Proc. of the 25th Annual ACM Symposium on Principles of Distributed Computing (PODC), pages 248-257, 2006. URL:
  5. Vassos Hadzilacos and Sam Toueg. A modular approach to fault-tolerant broadcasts and related problems. Technical report, Cornell University, 1994. Google Scholar
  6. James Hendricks, Gregory R. Ganger, and Michael K. Reiter. Low-overhead Byzantine fault-tolerant storage. In Proc. of the 21st ACM SIGOPS Symposium on Operating Systems Principles (SOSP), pages 73-86, 2007. URL:
  7. Hugo Krawczyk. Secret sharing made short. In Proc. of the 13th Annual International Cryptology Conference on Advances in Cryptology (CRYPTO), pages 136-146, 1993. URL:
  8. Leslie Lamport. Lower bounds for asynchronous consensus. Distributed Computing, 19(2):104-125, 2006. URL:
  9. James S Plank. Erasure codes for storage systems: A brief primer. The USENIX Magazine, 38(6):44-50, 2013. Google Scholar
  10. Michael Rabin. Efficient dispersal of information for security, load balancing, and fault tolerance. Journal of the ACM (JACM), 36(2):335-348, 1989. URL:
  11. Jason K. Resch and James S. Plank. AONT-RS: Blending security and performance in dispersed storage systems. In Proc. of the 9th USENIX Conference on File and Storage Technologies (FAST), page 14, 2011. Google Scholar