{
  "id": "0803.4226",
  "version": "v5",
  "published": "2008-03-31T12:58:10.000Z",
  "updated": "2008-09-11T06:37:24.000Z",
  "title": "Security proof for QKD systems with threshold detectors",
  "authors": [
    "Toyohiro Tsurumaru",
    "Kiyoshi Tamaki"
  ],
  "comment": "6 pages, 4 figures; references changed; revised argument for the security proof; typos corrected",
  "journal": "Phys. Rev. A 78, 032302 (2008)",
  "doi": "10.1103/PhysRevA.78.032302",
  "categories": [
    "quant-ph"
  ],
  "abstract": "In this paper, we rigorously prove the intuition that in security proofs for BB84 one may regard an incoming signal to Bob as a qubit state. From this result, it follows that all security proofs for BB84 based on a virtual qubit entanglement distillation protocol, which was originally proposed by Lo and Chau [H.-K. Lo and H. F. Chau, Science 283, 2050 (1999)], and Shor and Preskill [P. W. Shor and J. Preskill, Phys. Rev. Lett. 85, 441 (2000)], are all valid even if Bob's actual apparatus cannot distill a qubit state explicitly. As a consequence, especially, the well-known result that a higher bit error rate of 20% can be tolerated for BB84 protocol by using two-way classical communications is still valid even when Bob uses threshold detectors. Using the same technique, we also prove the security of the Bennett-Brassard-Mermin 1992 (BBM92) protocol where Alice and Bob both use threshold detectors.",
  "revisions": [
    {
      "version": "v5",
      "updated": "2008-09-11T06:37:24.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "03.67.Dd"
    ],
    "keywords": [
      "security proof",
      "threshold detectors",
      "qkd systems",
      "virtual qubit entanglement distillation protocol",
      "qubit state"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review A",
      "year": 2008,
      "month": "Sep",
      "volume": 78,
      "number": 3,
      "pages": "032302"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2008PhRvA..78c2302T"
    }
  }
}