Security of differential quadrature phase shift quantum key distribution

Abstract

One of the simplest methods for implementing quantum key distribution over fiber-optic communication is the Bennett-Brassard 1984 protocol with phase encoding (PE-BB84 protocol), in which the sender uses phase modulation over double pulses from a laser and the receiver uses a passive delayed interferometer. Using essentially the same setup and by regarding a train of many pulses as a single block, one can carry out the so-called differential quadrature phase shift (DQPS) protocol, which is a variant of differential phase shift (DPS) protocols. Here we prove the security of the DQPS protocol based on an adaptation of proof techniques for the BB84 protocol, which inherits the advantages arising from the simplicity of the protocol, such as accommodating the use of threshold detectors and simple off-line calibration methods for the light source. We show that the secure key rate of the DQPS protocol in the proof is eight thirds as high as the rate of the PE-BB84 protocol.

Citation of the Fig.1 in the text corrected

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Cited by in corpus (8)

• Advances in Quantum Cryptography
• Advanced Laser Technology for Quantum Communications (Tutorial Review)
• A direct GHz-clocked phase and intensity modulated transmitter applied to quantum key distribution
• Refined security proof of the round-robin differential phase shift quantum key distribution and its improved performance in the finite-sized case
• Manipulating photon coherence to enhance the security of practical quantum key distribution
• Finite-key analysis for quantum key distribution with weak coherent pulses based on Bernoulli sampling
• Differential-phase-shift QKD with practical Mach-Zehnder interferometer
• Tight scaling of key rate for differential-phase-shift quantum key distribution