Paper 2025/489 Original: eprint.iacr.org/2025/489 ↗

Translating Between the Common Haar Random State Model and the Unitary Model

Eli Goldin
Mark Zhandry
Abstract

Black-box separations are a cornerstone of cryptography, indicating barriers to various goals. A recent line of work has explored black-box separations for quantum cryptographic primitives. Namely, a number of separations are known in the Common Haar Random State (CHRS) model, though this model is not considered a complete separation, but rather a starting point. A few very recent works have attempted to lift these separations to a unitary separation, which are considered complete separations. Unfortunately, we find significant errors in some of these lifting results. We prove general conditions under which CHRS separations can be generically lifted, thereby giving simple, modular, and bug-free proofs of complete unitary separations between various quantum primitives. Our techniques allow for simpler proofs of existing separations as well as new separations that were previously only known in the CHRS model.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint.
History
2025-07-23: last updated
2025-03-14: published
Short URL
https://ia.cr/2025/489
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2025/489,
      author = {Eli Goldin and Mark Zhandry},
      title = {Translating Between the Common Haar Random State Model and the Unitary Model},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/489},
      year = {2025},
      url = {https://eprint.iacr.org/2025/489}
}
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