Paper 2023/1347

Decentralised Repeated Modular Squaring Service Revisited: Attack and Mitigation

Aydin Abadi, University College London
Abstract

Repeated modular squaring plays a crucial role in various time-based cryptographic primitives, such as Time-Lock Puzzles and Verifiable Delay Functions. At ACM CCS 2021, Thyagarajan et al. introduced “OpenSquare”, a decentralised protocol that lets a client delegate the computation of repeated modular squaring to third-party servers while ensuring that these servers are compensated only if they deliver valid results. In this work, we unveil a significant vulnerability in OpenSquare, which enables servers to receive payments without fulfilling the delegated task. To tackle this issue, we present a series of mitigation measures.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
Keywords
CryptanalysisDelegated ComputationRepeated Modular SquaringTime-Lock PuzzleVerifiable Delay FunctionBlockchain
Contact author(s)
aydin abadi @ ucl ac uk
History
2024-05-07: revised
2023-09-09: received
See all versions
Short URL
https://ia.cr/2023/1347
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2023/1347,
      author = {Aydin Abadi},
      title = {Decentralised Repeated Modular Squaring Service Revisited: Attack and Mitigation},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1347},
      year = {2023},
      url = {https://eprint.iacr.org/2023/1347}
}
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