Photon-number Splitting Attack Research Articles

Quantum cryptography protocols robust against photon number splitting attacks for weak laser pulse implementations.

We introduce a new class of quantum key distribution protocols, tailored to be robust against photon number splitting (PNS) attacks. We study one of these protocols, which differs from the original protocol by Bennett and Brassard (BB84) only in the classical sifting procedure. This protocol is provably better than BB84 against PNS attacks at zero error.

Eavesdropping on practical quantum cryptography

Practical implementations of quantum cryptography use attenuated laser pulses as the signal source rather than single photons. The channels used to transmit are also lossy. Here we give a simple derivation of two beamsplitting attacks on quantum cryptographic systems using laser pulses, either coherent or mixed states with any mean photon number. We also give a simple derivation of a photon-number splitting attack, the most advanced, both in terms of performance and technology required. We find bounds on the maximum disturbance for a given mean photon number and observed channel transmission efficiency for which a secret key can be distilled. We start by reviewing two incoherent attacks that can be used on single photon quantum cryptographic systems. These results are then adapted to systems that use laser pulses and lossy channels.

Eavesdropping on practical quantum cryptography

Abstract Practical implementations of quantum cryptography use attenuated laser pulses as the signal source rather than single photons. The channels used to transmit are also lossy. Here we give a simple derivation of two beamsplitting attacks on quantum cryptographic systems using laser pulses, either coherent or mixed states with any mean photon number. We also give a simple derivation of a photon-number splitting attack, the most advanced, both in terms of performance and technology required. We find bounds on the maximum disturbance for a given mean photon number and observed channel transmission efficiency for which a secret key can be distilled. We start by reviewing two incoherent attacks that can be used on single photon quantum cryptographic systems. These results are then adapted to systems that use laser pulses and lossy channels.

Quantum key distribution with realistic states:photon-number statistics in the photon-number splitting attack

Quantum key distribution can be performed with practical signalsources such as weak coherent pulses. One example of such ascheme is the Bennett-Brassard protocol that can be implementedvia polarization of the signals, or equivalent signals. Itturns out that the most powerful tool at the disposition of aneavesdropper is the photon-number splitting attack. We show thatthis attack can be extended in the relevant parameter regimeso as to preserve the Poissonian photon number distribution ofthe combination of the signal source and the lossy channel.