Quantum key distribution breaking limits

Tinku Adhikari, Arindam Ghosh, Ajoy Kumar Khan +3 more

Distribution of keys in classical cryptography is one of the most significant affairs to deal with. The computational hardness is the fundamental basis of the security of these keys. However, in the era of quantum computing, quantum computers can break down these keys with their substantially more computation capability than normal computers. For instance, a quantum computer can easily break down RSA or ECC in polynomial time. In order to make the keys quantum resistant, Quantum Key Distribution (QKD) is developed to enforce security of the classical cryptographic keys from the attack of quantum computers. By using quantum mechanics, QKD can reinforce the durability of the keys of classical cryptography, which were practically unbreakable during the pre-quantum era. Thus, an extensive study is required to understand the importance of QKD to make the classical cryptographic key distributions secure against both classical and quantum computers. Therefore, in this paper, we discuss trends and limitations of key management protocols in classical cryptography, and demonstrates a relative study of different QKD protocols. In addition, we highlight the security implementation aspects of QKD, which lead to the solution of threats occurring in a quantum computing scenario, such that the cryptographic keys can be quantum resistant.

G. Ribordy, Nicolas Gisin, Hugo Zbinden

Lai Zhou, Jinping Lin, Yuan-Mei Xie +4 more

We achieve a finite-size key rate of 42.64bps over 508km fibers, breaking the fundamental rate-loss limit of point-point quantum key distribution (QKD), via implementing an innovative measurement-device-independent QKD through asynchronous coincidence pairing.

Lanlan Zhang, Xiangxiang Li, Hao Yu +2 more

Non-Interfering quantum key distribution (NI-QKD) is a novel QKD protocol which can surpass the limit of secure key capacity, which utilizes the characteristics of noninterference between orthogonal polarization states to obtain high key rates without interference. However, its practical application will be limited by the use of weak coherent source (WCS), which has a higher ratio of vacuum state pulses. To overcome the limitation of WCSs, we propose a NI-QKD protocol by using heralded pair coherent source (HNI-QKD), where the response of the right detector and the response of both detectors are defined as the effective events. The HNI-QKD can break the PLOB bound, the key generation performance has been improved by the advantage of the lower ratio of vacuum state pulses in HPCS. Compared to the NI-QKD protocol by using WCS, the HNI-QKD protocol can increase key generation rate and improve the secure transmission distance.

Roger Colbeck, Dejan Dukaric, Matthias Fitzi +1 more