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 beam-splitting 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.

to appear in J. Mod. Opt

References in corpus (4)

• Quantum Cryptography
• Security of quantum key distribution using d-level systems
• Quantum key distribution with realistic states: photon-number statistics in the photon-number splitting attack
• Faint laser quantum key distribution: Eavesdropping exploiting multiphoton pulses

Cited by in corpus (4)

• Photon-Number-Splitting versus Cloning Attacks in Practical Implementations of the Bennett-Brassard 1984 protocol for Quantum Cryptography
• Maximum nonlocality and minimum uncertainty using magic states
• Noise and measurement errors in a practical two-state quantum bit commitment protocol
• Attacking quantum key distribution with single-photon two-qubit quantum logic