9-13 July 2012
Derivation of the quantum-bit-error rate for the BB84 protocol based on the phase-covariant-cloning machine
Presented by Mr. Mhlambululi MAFU on 11 Jul 2012 from 08:20 to 08:40
Type: Oral Presentation
Track: Track G - Theoretical and Computational Physics
Quantum key distribution provides the only physically secure and proven method for the transmission of a secret key between two distant parties, Alice and Bob who are connected by an authenticated classical channel and insecure quantum channel . Based on the laws of physics in particular the no-cloning theorem , quantum key distribution makes possible the distribution of the secret key such that the third party, Eve cannot clone the quantum states of the BB84 protocol sent by Alice and then re-send a perfect copy to the receiver (Bob) without it being de- tected. However, the phase-covariant-cloning machine  seems to be the best cloning machine for the BB84 quantum states. Therefore, we high- light that there is a trade-off between the quality of the clone and the amount of information that Eve can gain but still the protocol remaining secure. By using the phase-covariant-cloning machine to illustrate strate- gies performed by the eavesdropper, we arrive at a quantum bit-error-rate of 0.1464 for the BB84 protocol which agrees with previous results [4, 5]. References  Valerio Scarani, Helle Bechmann-Pasquinucci, Nicolas J. Cerf, Miloslav Duˇsek, Norbert Lu ̈tkenhaus, and Momtchil Peev. The security of practi- cal quantum key distribution. Rev. Mod. Phys., 81(3):1301–1350, Sep 2009.  M.A. Nielsen and I.L. Chuang. Quantum Computation and Quantum Infor- mation. Cambridge University Press, 2002.  D. Bruss, M. Cinchetti, G. Mauro DAriano, and C. Macchiavello. Phase- covariant quantum cloning. Physical Review A, 62(1):12302, 2000.  P.W. Shor and J. Preskill. Simple proof of security of the bb84 quantum key distribution protocol. Physical Review Letters, 85(2):441–444, 2000.  C. Branciard, N. Gisin, B. Kraus, and V. Scarani. Security of two quantum cryptography protocols using the same four qubit states. Physical Review A, 72(3):32301, 2005.
Prof Francesco Petruccione, email@example.com. Quantum Research Group, University of KwaZulu-Natal.
- Prof. Francesco PETRUCCIONE Quantum Research Group, National Institute for Theoretical Physics and School of Chemistry and Physics, University of KwaZulu-Natal