{
  "abstract": "We introduce information-theoretically private quantum protocols for two-party Hamming distance when both parties must output the same estimate. Classically, for input length $n$, information-theoretic protocols require $Ω(\\sqrt{n})$ error under pure differential privacy and $Ω(\\sqrt{n}/\\log n)$ error under strong approximate differential privacy, whereas computational security permits $O(1)$ error. In Klauck's honest, nonpreemptive, message-preserving model, we give an $O(n)$-communication quantum protocol with pure $\\varepsilon$ quantum differential privacy (QDP) and expected error at most $\\frac{2}{\\sinh \\varepsilon}+γ$, for every $γ>0$. For approximate $(\\varepsilon, δ)$ QDP, an exact hockey-stick divergence calculation yields strictly smaller error, while preserving the $O(1)$-versus-$Ω(\\sqrt{n}/\\log n)$ separation for $δ=o(1/n)$. Thus, quantum communication achieves $O(1)$ information-theoretic error, matching the accuracy available classically only under computational assumptions. The main construction uses a guarded coherent round trip and an equal-Gram rigidity principle that prevents an honest player from retaining input-dependent complementary information. We separate this model from weaker prescribed-channel privacy, which already admits an exact classical realization, and from fully retention-robust security, against which measurement-and-abort attacks remain possible. Therefore, we identify preservation of non-orthogonal quantum messages as a resource for privacy.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.02113",
  "author_total": 2,
  "authors": [
    {
      "name": "Daniel Alabi"
    },
    {
      "name": "Emil T. Khabiboulline"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2vk1dynp19dbj.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.02113",
  "fulltext_url": null,
  "id": "2vk1dynp19dbj",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.02113",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cs.CR"
    ],
    [
      "arxiv",
      "cs.IT"
    ],
    [
      "arxiv",
      "math.IT"
    ],
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "1702|Quantum Information and Cryptography"
    ]
  ],
  "openalex": "W7215781087",
  "pdf_url": "https://arxiv.org/pdf/2610.02113",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2vk1dynp19dbj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2610.02113",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.02113"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.IT",
      "subfield": "general"
    },
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Quantum Advantage for Two-Party Differential Privacy",
  "title_text": "Quantum Advantage for Two-Party Differential Privacy",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:07Z",
  "url": "https://research.draconitic.com/paper/2vk1dynp19dbj",
  "venue": "arXiv",
  "versions": []
}