{
  "annotation_id": "ad40a4bc-4e1e-410d-b2d0-8e40e448d7ba",
  "date_created": "2026-03-02T18:02:06.283000Z",
  "date_modified": "2026-03-02T18:02:06.283000Z",
  "file_hash": "c97905cb3a435e5f19358cd06917d02ba300187fc12a260353a9566e455c3dc3",
  "private": false,
  "record": {
    "abstract": "It is demonstrated that for the entanglement-based version of the\nBennett-Brassard (BB84) quantum key distribution protocol, Alice and Bob share\nprovable entanglement if and only if the estimated qubit error rate is below\n25% or above 75%. In view of the intimate relation between entanglement and\nsecurity, this result sheds also new light on the unconditional security of the\nBB84 protocol in its original prepare-and-measure form. In particular, it\nindicates that for small qubit error rates 25% is the ultimate upper security\nbound for any prepare-and-measure BB84-type QKD protocol. On the contrary, for\nqubit error rates between 25% and 75% we demonstrate that the correlations\nshared between Alice and Bob can always be explained by separable states and\nthus, no secret key can be distilled in this regime.",
    "arxiv_id": "quant-ph/0403148",
    "authors": [
      "Georgios M. Nikolopoulos",
      "Gernot Alber"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1140/epjd/e2005-00314-3",
    "journal_ref": "Eur. Phys. J. D 37, 441 (2006)",
    "title": "Robustness of the BB84 quantum key distribution protocol against general   coherent attacks",
    "url": "https://arxiv.org/abs/quant-ph/0403148"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "30b51fa7-88b5-4f6b-a17b-ead13fdce16d",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}