Entanglement enhances security in quantum communication
- Institute of Physics, Nicolaus Copernicus University, ul. Grudziadzka 5, 87-100 Torun (Poland)
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)
- Institut de Ciencies Fotoniques (ICFO), E-08860 Castelldefels, Barcelona (Spain)
Secret sharing is a protocol in which a 'boss' wants to send a classical message secretly to two 'subordinates', such that none of the subordinates is able to know the message alone, while they can find it if they cooperate. Quantum mechanics is known to allow for such a possibility. We analyze tolerable quantum bit error rates in such secret sharing protocols in the physically relevant case when the eavesdropping is local with respect to the two channels of information transfer from the boss to the two subordinates. We find that using entangled encoding states is advantageous to legitimate users of the protocol. We therefore find that entanglement is useful for secure quantum communication. We also find that bound entangled states with positive partial transpose are not useful as a local eavesdropping resource. Moreover, we provide a criterion for security in secret sharing--a parallel of the Csiszar-Koerner criterion in single-receiver classical cryptography.
- OSTI ID:
- 21313221
- Journal Information:
- Physical Review. A, Vol. 80, Issue 1; Other Information: DOI: 10.1103/PhysRevA.80.012311; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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