Security of two-state and four-state practical quantum bit-commitment protocols
| Autor: | Loura, Ricardo, Arsenović, Dušan, Paunković, Nikola, Popović, Duška B., Prvanović, Slobodan |
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| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Phys. Rev. A 94, 062335 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevA.94.062335 |
| Popis: | We study cheating strategies against a practical four-state quantum bit-commitment protocol and its two-state variant when the underlying quantum channels are noisy and the cheating party is constrained to using single-qubit measurements only. We show that simply inferring the transmitted photons' states by using the Breidbart basis, optimal for ambiguous (minimum-error) state discrimination, does not directly produce an optimal cheating strategy for this bit-commitment protocol. We introduce a new strategy, based on certain post-measurement processes, and show it to have better chances at cheating than the direct approach. We also study to what extent sending forged geographical coordinates helps a dishonest party in breaking the binding security requirement. Finally, we investigate the impact of imperfect single-photon sources in the protocols. Our study shows that, in terms of the resources used, the four-state protocol is advantageous over the two-state version. The analysis performed can be straightforwardly generalised to any finite-qubit measurement, with the same qualitative results. Comment: 20 pages, 9 figures, published version |
| Databáze: | arXiv |
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