Paper 2025/1064

Achieving Blockchain-Secured Cryptographic Primitives from Signature-Based Witness Encryption

Lev Stambler, University of Maryland, College Park
Abstract

Goyal and Goyal demonstrated that extractable witness encryption, when combined with smart-contract equipped proof-of-stake blockchains, can yield powerful cryptographic primitives such as one-time programs and pay-to-use programs. However, no standard model construction for extractable witness encryption is known, and instantiations from alternatives like indistinguishability obfuscation are highly inefficient. This paper circumvents the need for extractable witness encryption by combining signature-based witness encryption (Döttling et al.) with witness encryption for KZG commitments (Fleischhacker et al.). Inspired by Goyal et al., we introduce $T+1$-Extractable Witness Encryption for Blockchains ($T+1$-eWEB), a novel primitive that encrypts a secret, making its decryption contingent upon the subsequent block's state. Leveraging $T+1$-eWEBs, we then build a conditional one-time memory, leading to a $T+1$ one-time program ($T+1$-OTP) also conditional on the next block's state.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
Keywords
blockchainwitness encryptionone-time programsobfuscationEthereum
Contact author(s)
levstamb @ umd edu
History
2025-10-09: last of 2 revisions
2025-06-06: received
See all versions
Short URL
https://ia.cr/2025/1064
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2025/1064,
      author = {Lev Stambler},
      title = {Achieving Blockchain-Secured Cryptographic Primitives from Signature-Based Witness Encryption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1064},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1064}
}
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