Post-quantum game-based security of ideal-cipher (O)EKE

Determine the post-quantum game-based security of (O)EKE instantiated with an ideal cipher, particularly in the quantum ideal cipher model.

Background

The paper establishes negative UC-security results for ideal-cipher OEKE and positive stand-alone game-based results for 2-Feistel OEKE in the QROM. It leaves unresolved the corresponding game-based security analysis for (O)EKE instantiated with an ideal cipher, especially in light of recent techniques for quantum-accessible random permutations.

References

One can also ask about the post-quantum game-based security of (O)EKE when instantiated with an ideal cipher, especially given recent techniques for analyzing quantum-accessible random permutations (e.g. [CHL+25, Car26, CM26]).

— Natural Barriers to Quantum Extraction: On the Post-Quantum (In)security of (O)EKE and Masny-Rindal OT  (2609.39844 - Bartusek et al., 30 Sep 2026) in Section 2.6, Future work, Security in the quantum ideal cipher model