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Measurement-Device-Independent Quantum Secure Direct Communication
Zeng-Rong Zhou, Yu-Bo Sheng, Peng-Hao Niu, Liu-Guo Yin, Gui-Lu Long
TL;DR
QSDC needs practical security against imperfect measurement devices, while transmitting secret information directly without keys or ciphertext. The paper proposes MDI-QSDC protocols using entangled pairs and single photons, including a linear-optics version, and presents a deterministic MDI-QKD reduction.
Problem
QSDC is secure under ideal conditions, so practical application requires protection against imperfections in measurement devices and other realistic conditions.
Method
The paper proposes MDI-QSDC using Alice’s EPR-pair sequence, Bob’s single photons, and Bell-basis measurement by an untrusted Charlie, with message encoding after security checking.
Results
The protocols eliminate measurement-device security loopholes, effectively double communication distance, and include a linear-optics version measuring only two Bell-basis states.
Takeaways & Limitations
When the block size is reduced to one qubit, MDI-QSDC reduces to a deterministic MDI-QKD protocol.
Takeaways & Limitations
QSDC’s security depends on block transmission: without it, eavesdroppers may access transmitted data before security confirmation.
Abstract
from arXiv · showhide
Quantum secure direct communication (QSDC) is the technology to transmit secret information directly through a quantum channel without neither key nor ciphertext. It provides us with a secure communication structure that is fundamentally different from the one that we use today. In this Letter, we report the first measurement-device-independent(MDI) QSDC protocol with sequences of entangled photon pairs and single photons. It eliminates security loopholes associated with the measurement device. In addition, the MDI technique doubles the communication distance compared to those without using the technique. We also give a protocol with linear optical Bell-basis measurement, where only two of the four Bell-basis states could be measured. When the number of qubit in a sequence reduces to 1, the MDI-QSDC protocol reduces to a deterministic MDI quantum key distribution protocol, which is also presented in the Letter.