Paper 2025/800

Comparing classical and quantum conditional disclosure of secrets

Uma Girish, Columbia University
Alex May, Perimeter Institute for Theoretical Physics, Institute for Quantum Computing
Leo Orshansky, Columbia University
Chris Waddell, Perimeter Institute for Theoretical Physics
Abstract

The conditional disclosure of secrets (CDS) setting is among the most basic primitives studied in information-theoretic cryptography. Motivated by a connection to non-local quantum computation and position-based cryptography, CDS with quantum resources has recently been considered. Here, we study the differences between quantum and classical CDS, with the aims of clarifying the power of quantum resources in information-theoretic cryptography. We establish the following results: 1) For perfectly correct CDS, we give a separation for a promise version of the not-equals function, showing a quantum upper bound of and classical lower bound of . 2) We prove a lower bound on quantum CDS where is the classical one-way communication complexity with perfect correctness. 3) We prove a lower bound on quantum CDS in terms of two round, public coin, two-prover interactive proofs. 4) We give a logarithmic upper bound for quantum CDS on forrelation, while the best known classical algorithm is linear. We interpret this as preliminary evidence that classical and quantum CDS are separated even with correctness and security error allowed. We also give a separation for classical and quantum private simultaneous message passing for a partial function, improving on an earlier relational separation. Our results use novel combinations of techniques from non-local quantum computation and communication complexity.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint.
Keywords
quantuminformation-theoretic cryptographyconditional disclosure of secretsCDSquantum-classical separations
Contact author(s)
ug2150 @ columbia edu
amay @ perimeterinstitute ca
lo2433 @ columbia edu
cwaddell @ perimeterinstitute ca
History
2025-05-05: approved
2025-05-05: received
See all versions
Short URL
https://ia.cr/2025/800
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2025/800,
      author = {Uma Girish and Alex May and Leo Orshansky and Chris Waddell},
      title = {Comparing classical and quantum conditional disclosure of secrets},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/800},
      year = {2025},
      url = {https://eprint.iacr.org/2025/800}
}
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