SARG04
Encyclopedia
SARG04 is a quantum cryptography protocol
derived from the first protocol of that kind, BB84
.
with a different information encoding they could develop a new protocol which would be more robust when attenuated laser
pulses are used instead of single-photon
sources. SARG04 was defined by Scarani et al. in 2004 in Physical Review Letters
as a prepare and measure version (in which it is equivalent to BB84 when viewed at the level of quantum processing).
An entanglement
-based version has been defined as well.
of SARG04 is based on the principle that the hardware
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 equal probability
.
Double clicks are important for comprehending SARG04: double clicks work differently in BB84 and SARG04.
It has been confirmed that SARG04 is more robust than BB84 against incoherent PNS attacks.
Unfortunately an incoherent attack has been identified which performs better than a simple phase-covariant cloning machine, and SARG04 has been found to be particularly vulnerable in single-photon implementations when Q >= 14.9%.
Quantum cryptography protocol
A quantum cryptography protocol is a protocol for quantum cryptography.The first quantum cryptography protocol, BB84, was defined in 1984.SARG04 is a recent quantum cryptography protocol...
derived from the first protocol of that kind, BB84
BB84
BB84 is a quantum key distribution scheme developed by Charles Bennett and Gilles Brassard in 1984. It is the first quantum cryptography protocol. The protocol is provably secure, relying on the quantum property that information gain is only possible at the expense of disturbing the signal if the...
.
Origin
Researchers built SARG04 when they noticed that by using the four states of BB84BB84
BB84 is a quantum key distribution scheme developed by Charles Bennett and Gilles Brassard in 1984. It is the first quantum cryptography protocol. The protocol is provably secure, relying on the quantum property that information gain is only possible at the expense of disturbing the signal if the...
with a different information encoding they could develop a new protocol which would be more robust when attenuated laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
pulses are used instead of single-photon
Photon
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
sources. SARG04 was defined by Scarani et al. in 2004 in Physical Review Letters
Physical Review Letters
Physical Review Letters , established in 1958, is a peer reviewed, scientific journal that is published 52 times per year by the American Physical Society...
as a prepare and measure version (in which it is equivalent to BB84 when viewed at the level of quantum processing).
An entanglement
Entanglement
Entanglement may refer to:* Quantum entanglement* Orientation entanglement* Entanglement * Entanglement of polymer chains, see Reptation* Wire 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 producing weak pulses (this means: mean number of photons < 1) and received by an imperfect detector.Modus operandi
The modus operandiModus operandi
Modus operandi is a Latin phrase, approximately translated as "mode of operation". The term is used to describe someone's habits or manner of working, their method of operating or functioning...
of SARG04 is based on the principle that the hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
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 equal probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
.
Double clicks are important for comprehending SARG04: double clicks work differently in BB84 and SARG04.
Security
Kiyoshi Tamaki and Hoi-Kwong 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 attacks.
Unfortunately an incoherent attack has been identified which performs better than a simple phase-covariant cloning machine, and SARG04 has been found to be particularly vulnerable in single-photon implementations when Q >= 14.9%.