Paper 2026/1691

Equivalence Between Average-Case Hardness of Learning and Cryptography for Mixed Quantum States

Alexandru Cojocaru, University of Edinburgh
Laura Lewis, University of Edinburgh, University of California, Berkeley
Abstract

The relationship between cryptography and learning theory has long been a central theme in the foundations of theoretical computer science: cryptographic primitives can imply hardness of learning, while hardness of learning can in turn be used to construct cryptographic schemes. Recent works have begun exploring analogous connections in the quantum setting, relating the average-case hardness of learning quantum states (AHL) to cryptographic primitives such as one-way state generators (OWSG). Despite recent progress exploring this for pure states, the relationship for mixed states has remained an open question. In this work, we prove that the existence of AHL for mixed quantum states is equivalent to the existence of inefficiently verifiable one-way state generators (IV-OWSGs). As a consequence, this relates mixed-state AHL to EFI pairs. Moreover, as a corollary of existing results, we obtain a separation between IV-OWSGs and OWSGs relative to the SWAP oracle.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint.
Keywords
quantum cryptography
Contact author(s)
a cojocaru @ ed ac uk
lllewis @ berkeley edu
History
2026-08-15: approved
2026-08-14: received
See all versions
Short URL
https://ia.cr/2026/1691
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2026/1691,
      author = {Alexandru Cojocaru and Laura Lewis},
      title = {Equivalence Between Average-Case Hardness of Learning and Cryptography for Mixed Quantum States},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/1691},
      year = {2026},
      url = {https://eprint.iacr.org/2026/1691}
}
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