SpringerLink
Log in

SNACKs: Leveraging Proofs of Sequential Work for Blockchain Light Clients

  • Conference paper
  • First Online:
Advances in Cryptology – ASIACRYPT 2022 (ASIACRYPT 2022)

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 13791))

  • 888 Accesses

Abstract

The success of blockchains has led to ever-growing ledgers that are stored by all participating full nodes. In contrast, light clients only store small amounts of blockchain-related data and rely on the mediation of full nodes when interacting with the ledger. A broader adoption of blockchains calls for protocols that make this interaction trustless.

We revisit the design of light-client blockchain protocols from the perspective of classical proof-system theory, and explain the role that proofs of sequential work (PoSWs) can play in it. To this end, we define a new primitive called succinct non-interactive argument of chain knowledge (SNACK), a non-interactive proof system that provides clear security guarantees to a verifier (a light client) even when interacting only with a single dishonest prover (a full node). We show how augmenting any blockchain with any graph-labeling PoSW (GL-PoSW) enables SNACK proofs for this blockchain. We also provide a unified and extended definition of GL-PoSWs covering all existing constructions, and describe two new variants. We then show how SNACKs can be used to construct light-client protocols, and highlight some deficiencies of existing designs, along with mitigations. Finally, we introduce incremental SNACKs which could potentially provide a new approach to light mining.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 99.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 129.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free ship** worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Similar content being viewed by others

Notes

  1. 1.

    The term light node or light client is sometimes used solely to refer to nodes adopting SPV (see below); we mean by it any node that does not store the full blockchain.

  2. 2.

    We use the words chain and blockchain as synonyms throughout the paper.

  3. 3.

    This is akin to f-extractability [BCKL08] of proof systems, which relaxes knowledge soundness by only requiring extraction of a partial witness (or a function thereof).

  4. 4.

    The PoSW of [DLM19] is defined and constructed non-interactively by employing an on-the-fly sampling technique.

  5. 5.

    Note that such a path exists since \(G_n\) has a unique sink.

  6. 6.

    Such honest parties are called alert in [PS17, BGK+18]; we will not maintain this distinction and will always assume honest parties to be alert.

References

  1. Abusalah, H., Alwen, J., Cohen, B., Khilko, D., Pietrzak, K., Reyzin, L.: Beyond Hellman’s time-memory trade-offs with applications to proofs of space. In: Takagi, T., Peyrin, T. (eds.) ASIACRYPT 2017. Part II, volume 10625 of LNCS, pp. 357–379. Springer, Heidelberg (2017). https://doi.org/10.1007/978-3-319-70697-9_13

    Chapter  Google Scholar 

  2. Abusalah, H., Fuchsbauer, G., Gaži, P., Klein, K.: SNACKs: Leveraging proofs of sequential work for blockchain light clients. Cryptology ePrint Archive, Report 2022/240 (2022). https://eprint.iacr.org/2022/240

  3. Abusalah, H., Kamath, C., Klein, K., Pietrzak, K., Walter, M.: Reversible proofs of sequential work. In: Ishai, Y., Rijmen, V. (eds.) EUROCRYPT 2019. Part II, volume 11477 of LNCS, pp. 277–291. Springer, Heidelberg (2019). https://doi.org/10.1007/978-3-030-17656-3_10

    Chapter  Google Scholar 

  4. Boneh, D., Bonneau, J., Bünz, B., Fisch, B.: Verifiable delay functions. In: Shacham, H., Boldyreva, A. (eds.) CRYPTO 2018. Part I, volume 10991 of LNCS, pp. 757–788. Springer, Heidelberg (2018). https://doi.org/10.1007/978-3-319-96884-1_25

    Chapter  Google Scholar 

  5. Back, A., et al.: Enabling Blockchain Innovations with Pegged Sidechains (2014). https://blockstream.com/sidechains.pdf. Accessed 16 Aug 2019

  6. Belenkiy, M., Chase, M., Kohlweiss, M., Lysyanskaya, A.: P-signatures and noninteractive anonymous credentials. In: Canetti, R. (ed.) TCC 2008. LNCS, vol. 4948, pp. 356–374. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-78524-8_20

    Chapter  Google Scholar 

  7. Badertscher, C., Gazi, P., Kiayias, A., Russell, A., Zikas, V.: Ouroboros genesis: composable proof-of-stake blockchains with dynamic availability. In: Lie, D., Mannan, M., Backes, M., Wang, X., (eds.), ACM CCS 2018, pp. 913–930. ACM Press (2018)

    Google Scholar 

  8. Bünz, B., Kiffer, L., Luu, L., Zamani, M.: FlyClient: super-light clients for cryptocurrencies. In: 2020 IEEE Symposium on Security and Privacy, pp. 928–946. IEEE (2020)

    Google Scholar 

  9. Bonneau, J., Meckler, I., Rao, V., Shapiro, E.: Coda: decentralized cryptocurrency at scale. Cryptology ePrint Archive, Report 2020/352 (2020). https://eprint.iacr.org/2020/352

  10. Badertscher, C., Maurer, U., Tschudi, D., Zikas, V.: Bitcoin as a transaction ledger: a composable treatment. In: Katz, J., Shacham, H. (eds.) CRYPTO 2017. Part I, volume 10401 of LNCS, pp. 324–356. Springer, Heidelberg (2017). https://doi.org/10.1007/978-3-319-63688-7_11

    Chapter  Google Scholar 

  11. Cohen, B., Pietrzak, K.: Simple proofs of sequential work. In: Nielsen, J.B., Rijmen, V. (eds.) EUROCRYPT 2018. LNCS, vol. 10821, pp. 451–467. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-78375-8_15

    Chapter  Google Scholar 

  12. Cohen, B., Pietrzak, K.: The Chia Network blockchain (2019). https://www.chia.net/assets/ChiaGreenPaper.pdf

  13. Dziembowski, S., Faust, S., Kolmogorov, V., Pietrzak, K.: Proofs of space. In: Gennaro, R., Robshaw, M. (eds.) CRYPTO 2015. LNCS, vol. 9216, pp. 585–605. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-662-48000-7_29

    Chapter  Google Scholar 

  14. David, B., Gaži, P., Kiayias, A., Russell, A.: Ouroboros praos: an adaptively-secure, semi-synchronous proof-of-stake blockchain. In: Nielsen, J.B., Rijmen, V. (eds.) EUROCRYPT 2018. LNCS, vol. 10821, pp. 66–98. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-78375-8_3

    Chapter  Google Scholar 

  15. Daveas, S., Karantias, K., Kiayias, A., Zindros, D.: A gas-efficient superlight bitcoin client in solidity. Cryptology ePrint Archive, Report 2020/927 (2020). https://eprint.iacr.org/2020/927

  16. Döttling, N., Lai, R.W.F., Malavolta, G.: Incremental proofs of sequential work. In: Ishai, Y., Rijmen, V. (eds.) EUROCRYPT 2019. LNCS, vol. 11477, pp. 292–323. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-17656-3_11

    Chapter  Google Scholar 

  17. Daian, P., Pass, R., Shi, E.: Snow white: robustly reconfigurable consensus and applications to provably secure proof of stake. In: Goldberg, I., Moore, T. (eds.) FC 2019. LNCS, vol. 11598, pp. 23–41. Springer, Heidelberg (2019). https://doi.org/10.1007/978-3-030-32101-7_2

    Chapter  Google Scholar 

  18. Fiat, A., Shamir, A.: How to prove yourself: practical solutions to identification and signature problems. In: Odlyzko, A.M. (ed.) CRYPTO’86. LNCS, vol. 263, pp. 186–194. Springer, Heidelberg (1987). https://doi.org/10.1007/3-540-47721-7_12

    Chapter  Google Scholar 

  19. Gennaro, R., Gentry, C., Parno, B., Raykova, M.: Quadratic span programs and succinct NIZKs without PCPs. In: Johansson, T., Nguyen, P.Q. (eds.) EUROCRYPT 2013. LNCS, vol. 7881, pp. 626–645. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-38348-9_37

    Chapter  Google Scholar 

  20. Garay, J., Kiayias, A., Leonardos, N.: The bitcoin backbone protocol: analysis and applications. In: Oswald, E., Fischlin, M. (eds.) EUROCRYPT 2015. LNCS, vol. 9057, pp. 281–310. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-662-46803-6_10

    Chapter  Google Scholar 

  21. Gazi, P., Kiayias, A., Zindros, D.: Proof-of-stake sidechains. In: 2019 IEEE Symposium on Security and Privacy, pp. 139–156. IEEE (2019)

    Google Scholar 

  22. Gaži, P., Ren, L., Russell, A.: Practical settlement bounds for proof-of-work blockchains. Cryptology ePrint Archive, Report 2021/805 (2021). https://eprint.iacr.org/2021/805

  23. Groth, J., Sahai, A.: Efficient non-interactive proof systems for bilinear groups. In: Smart, N.P. (ed.) EUROCRYPT 2008. LNCS, vol. 4965, pp. 415–432. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-78967-3_24

    Chapter  Google Scholar 

  24. Karantias, K., Kiayias, A., Zindros, D.: Compact storage of superblocks for NIPoPoW applications. In: Pardalos, P., Kotsireas, I., Guo, Y., Knottenbelt, W. (eds.) Mathematical Research for Blockchain Economy. SPBE, pp. 77–91. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-37110-4_6

    Chapter  MATH  Google Scholar 

  25. Kiayias, A., Lamprou, N., Stouka, A.-P.: Proofs of proofs of work with sublinear complexity. In: Clark, J., Meiklejohn, S., Ryan, P.Y.A., Wallach, D., Brenner, M., Rohloff, K. (eds.) FC 2016. LNCS, vol. 9604, pp. 61–78. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-53357-4_5

    Chapter  Google Scholar 

  26. Kiayias, A., Leonardos, N., Zindros, D.: Mining in logarithmic space. In: Vigna, G., Shi, E., (eds.), ACM CCS 2021, pp. 3487–3501. ACM Press (2021)

    Google Scholar 

  27. Kiayias, A., Miller, A., Zindros, D.: Non-interactive proofs of proof-of-work. In: Bonneau, J., Heninger, N. (eds.) FC 2020. LNCS, vol. 12059, pp. 505–522. Springer, Heidelberg (2020). https://doi.org/10.1007/978-3-030-51280-4_27

    Chapter  Google Scholar 

  28. Kiayias, A., Polydouri, A., Zindros, D.: The velvet path to superlight blockchain clients. Cryptology ePrint Archive, Report 2020/1122 (2020). https://eprint.iacr.org/2020/1122

  29. Kiayias, A., Russell, A., David, B., Oliynykov, R.: Ouroboros: a provably secure proof-of-stake blockchain protocol. In: Katz, J., Shacham, H. (eds.) CRYPTO 2017. Part I, volume 10401 of LNCS, pp. 357–388. Springer, Heidelberg (2017). https://doi.org/10.1007/978-3-319-63688-7_12

    Chapter  Google Scholar 

  30. Kiayias, A., Zindros, D.: Proof-of-work sidechains. In: Bracciali, A., Clark, J., Pintore, F., Rønne, P.B., Sala, M. (eds.) FC 2019 Workshops. LNCS, vol. 11599, pp. 21–34. Springer, Heidelberg (2019). https://doi.org/10.1007/978-3-030-43725-1_3

    Chapter  Google Scholar 

  31. Mahmoody, M., Moran, T., Vadhan, S.: Publicly verifiable proofs of sequential work. In: Robert, D., Kleinberg, J., editor, ITCS 2013, pp. 373–388. ACM (2013)

    Google Scholar 

  32. Nakamoto, S.: Bitcoin: A Peer-to-Peer Electronic Cash System (2008). https://bitcoin.org/bitcoin.pdf. Accessed 19 June 2018

  33. Pietrzak, K.: Simple verifiable delay functions. In Blum, A., editor, ITCS 2019, vol. 124, pp. 60:1–60:15. LIPIcs (2019)

    Google Scholar 

  34. Pass, R., Shi, E.: The sleepy model of consensus. In: Takagi, T., Peyrin, T. (eds.) ASIACRYPT 2017. Part II, volume 10625 of LNCS, pp. 380–409. Springer, Heidelberg (2017). https://doi.org/10.1007/978-3-319-70697-9_14

    Chapter  Google Scholar 

  35. Pass, R., Seeman, L., Shelat, A.: Analysis of the blockchain protocol in asynchronous networks. In: Coron, J.-S., Nielsen, J.B. (eds.) EUROCRYPT 2017. LNCS, vol. 10211, pp. 643–673. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-56614-6_22

    Chapter  MATH  Google Scholar 

  36. Vesely, P., et al.: Plumo: An ultralight blockchain client. Cryptology ePrint Archive, Report 2021/1361 (2021). https://eprint.iacr.org/2021/1361

  37. Wesolowski, B.: Efficient verifiable delay functions. In: Ishai, Y., Rijmen, V. (eds.) EUROCRYPT 2019. Part III, volume 11478 of LNCS, pp. 379–407. Springer, Heidelberg (2019). https://doi.org/10.1007/978-3-030-17659-4_13

    Chapter  Google Scholar 

Download references

Acknowledgements

The first two authors are supported by the Vienna Science and Technology Fund (WWTF) through project VRG18-002. The first author has also received funding in part from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program under project PICOCRYPT (grant agreement No. 101001283), the Spanish Government under projects SCUM (ref. RTI2018-102043-B-I00), the Madrid Regional Government under project BLOQUES (ref. S2018/TCS-4339), and a research grant from Nomadic Labs and the Tezos Foundation. The last author is supported in part by ERC CoG grant 724307 and conducted part of this work at ISTA, funded by the ERC under the European Union’s Horizon 2020 research and innovation programme (682815 - TOCNeT).

Author information

Authors and Affiliations

  1. IMDEA Software Institute, Madrid, Spain

    Hamza Abusalah

  2. TU Wien, Vienna, Austria

    Georg Fuchsbauer

  3. IOG, Chennai, India

    Peter Gaži

  4. ETH Zurich, Zürich, Switzerland

    Karen Klein

Authors
  1. Hamza Abusalah
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Georg Fuchsbauer
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Peter Gaži
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Karen Klein
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Hamza Abusalah .

Editor information

Editors and Affiliations

  1. Indian Institute of Technology Madras, Chennai, India

    Shweta Agrawal

  2. Chinese Academy of Sciences, Bei**g, China

    Dongdai Lin

Rights and permissions

Reprints and permissions

Copyright information

© 2022 International Association for Cryptologic Research

About this paper

Check for updates. Verify currency and authenticity via CrossMark

Cite this paper

Abusalah, H., Fuchsbauer, G., Gaži, P., Klein, K. (2022). SNACKs: Leveraging Proofs of Sequential Work for Blockchain Light Clients. In: Agrawal, S., Lin, D. (eds) Advances in Cryptology – ASIACRYPT 2022. ASIACRYPT 2022. Lecture Notes in Computer Science, vol 13791. Springer, Cham. https://doi.org/10.1007/978-3-031-22963-3_27

Download citation

  • DOI: https://doi.org/10.1007/978-3-031-22963-3_27

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-031-22962-6

  • Online ISBN: 978-3-031-22963-3

  • eBook Packages: Computer ScienceComputer Science (R0)

Publish with us

Policies and ethics

Search

Navigation