- SARG04
SARG04 is a
quantum cryptography protocol derived from the first protocol of that kind,BB84 .Origin
Researchers built SARG04 when they noticed that by using the four states of
BB84 with a differentinformation encoding they could develop a new protocol which would be more robust when attenuatedlaser pulses are used instead of single-photon sources. SARG04 was defined by Scarani et al in 2004 inPhysical Review Letters as aprepare and measure version (in which it is equivalent to BB84 when viewed at the level ofquantum processing ).http://arxiv.org/abs/quant-ph/0505035]An
entanglement -based version has been defined as well.Intended use
The intended use of SARG04 is in situations where the information is originated by a
Poissonian source producingweak pulse s (this means: mean number of photons < 1) and received by animperfect detector .Modus operandi
The
modus operandi of SARG04 is based on the principle that thehardware must remain the same (as prior protocols) and the only change must be in the protocol itself.In the original "prepare and measure" version, SARG04's two
conjugated bases are chosen with equalprobability .Double clicks are important for comprehending SARG04: double clicks work differently in BB84 and SARG04.
ecurity
Tamaki and Lo were successful in proving security for one and two-photon pulses using SARG04.
It has been confirmed that SARG04 is more robust than BB84 against
incoherent PNS attack s.Unfortunately an
incoherent attack has been identified which performs better than a simplephase-covariant cloning machine , and SARG04 has been found to be particularly vulnerable in single-photon implementations when Q >= 14.9%.Comparison with BB84
In single-photon implementations, SARG04 was theorised to be equal with BB84, but experiments shown that it is inferior.
Bibliography
* [http://www.citebase.org/abstract?id=oai%3AarXiv.org%3Aquant-ph%2F0510025]
* [http://arxiv.org/abs/quant-ph/0510025v1]
* [http://adsabs.harvard.edu/abs/2005PhRvA..72c2301B]References
ee also
*
Quantum cryptography
*BB84 protocol
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