Confidential communication is vital in modern society. Quantum secure direct communication is a new kind of secure communication with no encryption. In a classical secure communication, the sender and the receiver have to share a secret key in advance, then a plaintext is encoded into ciphertext, and sent to receiver through a classical channel. The ciphertext is then decoded to plaintext by receiver to complete the communication. In this structure, there exist three potential security loopholes, which are: (1) loss of key during the distribution process; (2) loss of key in storage and management; (3) interception of ciphertext by Eve for later cryptanalysis. With the development of supercomputers and quantum computers, these threats become more and more serious.
Quantum communication whose security is guarded by quantum physics principles is an important scheme resists these attacks. Quantum secure direct communication (QSDC) is a unique in its kind of secure communication, which does not require key distribution, key storage and management, and does not use ciphertext. It eliminates the three loopholes in classical secure communication efficiently.
The key problem of practical QSDC is that apparatuses used in practical quantum communication system have some defects, and these imperfections, especially defects in the measurement devices, can lead to leakage of information and affect the security of practical QSDC. Recently, a research team led by Prof. Gui-Lu Long from Tsinghua University proposed a measurement- device- independent (MDI) QSDC protocol using Einstein-Podolsky-Rosen pairs. This protocol eliminates all loopholes related to measurement devices, overcoming a key obstacle of practical QSDC. Besides, the MDI-QSDC has a twice communication distance, and a high communication capacity.
This work was supported by the National Basic Research Program of China under Grant Nos. 2017YFA0303700 and 2015CB921001, National Natural Science Foundation of China under Grant Nos. 61726801, 11474168 and 11474181.
See the article:
Peng-Hao Niu, Zeng-Rong Zhou, Zai-Sheng Lin, Yu-Bo Sheng, Liu-Guo Yin, and Gui-Lu Long. Measurement-Device-Independent Quantum Communication without Encryption, Science Bulletin, doi.org/10.1016/j.scib.2018.09.009, 2018