English

Coherent eavesdropping strategies for the 4-state quantum cryptography protocol

Quantum Physics 2009-10-30 v1

Abstract

An elementary derivation of best eavesdropping strategies for the 4 state BB84 quantum cryptography protocol is presented, for both incoherent and two--qubit coherent attacks. While coherent attacks do not help Eve to obtain more information, they are more powerful to reveal the whole message sent by Alice. Our results are based on symmetric eavesdropping strategies, which we show to be sufficient to analyze these kind of problems.

Keywords

Cite

@article{arxiv.quant-ph/9702002,
  title  = {Coherent eavesdropping strategies for the 4-state quantum cryptography protocol},
  author = {J. I. Cirac and N. Gisin},
  journal= {arXiv preprint arXiv:quant-ph/9702002},
  year   = {2009}
}

Comments

6 pages of LaTeX and 3 eps figures. Submitted to Phys. Lett. A