Paper 2023/806

SNACKs for Proof-of-Space Blockchains

Hamza Abusalah, IMDEA Software Institute, Madrid, Spain

SNACKs are succinct non-interactive arguments of chain knowledge. They allow for efficient and generic solutions to blockchain light-client bootstrapping. Abusalah et al. construct SNACKs in the random oracle model for any \emph{single-chain} blockchain from any graph-labeling proof of sequential work (PoSW) scheme. Their SNACK construction is a PoSW-like protocol over the augmented blockchain. Unlike single-chain blockchains, such as proof-of-work and proof-of-stake blockchains, proof-of-space (PoSpace) blockchains are composed of two chains: a \emph{canonical} proof chain and a data chain. These two chains are related using a signature scheme. In this work, we construct PoSW-enabled SNACKs for any PoSpace blockchain. Combined with the results of Abusalah et al., this gives the first solution to light-client bootstrapping in PoSpace blockchains. The space cost of our construction is \emph{two} hash values in each augmented PoSpace block. Generating SNACK proofs for a PoSpace blockchain is identical to generating SNACK proofs for single-chain blockchains and amounts to looking up a succinct number of augmented blocks.

Note: This is the full version.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Financial Cryptography and Data Security 2023
blockchainlight clientsbootstrappingproof of sequential workproof of space
Contact author(s)
hamzaabusalah @ gmail com
2023-06-06: approved
2023-06-01: received
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Creative Commons Attribution


      author = {Hamza Abusalah},
      title = {SNACKs for Proof-of-Space Blockchains},
      howpublished = {Cryptology ePrint Archive, Paper 2023/806},
      year = {2023},
      note = {\url{}},
      url = {}
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