Quantum Spectral Authentication under Public Unitary Challenges

Quantum Physics [Submitted on 25 Mar 2026] Quantum Spectral Authentication under Public Unitary Challenges S. P. Kish, H. J. Vallury, J. Pieprzyk, C. Thapa, S. Camtepe We introduce Quantum Spectral Authentication (QSA), a primitive for verifying that a remote quantum endpoint still possesses a previously installed secret quantum resource, such as a hidden state or state-preparation capability, without revealing that secret. QSA uses fresh public unitary challenges and spectral features of the planted state to derive transcript-bound session material for explicit authentication. We analyse attack strategies including eigenstate propagation across challenges, repeated-session leakage, and direct online forgery. For practical implementation, we develop a symmetric verifier-driven unitary compiler compatible with low-depth quantum phase estimation. Simulations indicate that this symmetric fast-power construction is substantially more noise tolerant than an asymmetric alternative, and small-instance experiments on IBM ibm_fez provide a hardware sanity check. QSA therefore offers a plausible near-term authentication layer for quantum networks and control-plane applications. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2603.24868 [quant-ph]   (or arXiv:2603.24868v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2603.24868 Focus to learn more Submission history From: Sebastian Kish Dr [view email] [v1] Wed, 25 Mar 2026 23:15:11 UTC (1,896 KB) Access Paper: view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-03 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)