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Optical Fiber Communication Conference

Security Analysis of Quantum Noise Stream Cipher under Fast Correlation Attack

Mingrui Zhang, Yajie Li, Haokun Song, Bo Wang, Yongli Zhao, Jie Zhang

Published Jan 1, 2021• 6 citations
Publisher

Abstract

We conduct an experiment of security analysis on 300km QAM/QNSC transmission under fast correlation attack. Noise masking model and hypothesis testing theory are adopted. Experiment results provide several solutions to achieve secure transmission in QAM/QNSC.
DOI
10.1364/ofc.2021.th1a.5

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This letter first reports a digital coherent quantum noise stream cipher (QNSC) experiment over 300km fiber without intermediate amplifiers. With the help of Raman fiber amplifiers, ultra-low loss fiber, and the optimized fuzzy C-means clustering algorithm, the results show the system can carry 10.2 Tbit/ s·km data, which is significantly improved in the single polarization and single wavelength digital coherent context without intermediate amplifiers. We further analyze the transmission and security performances under the 16 quadrature amplitude modulation (QAM) scenario in detail. The number of masked signals of 16 QAM/QNSC is 3843.2.
A ciphertext mapping method based on Gray code is proposed to improve the security of quantum noise stream cipher (QNSC). The experiment is conducted in 1024 × 1024 -quadrature amplitude modulation (QAM) coherent optical communication system over 300 km. Experimental results verify that the proposed scheme does not affect the transmission performance. Meanwhile, the performance analysis reveals that the attacker's bit error rate (BER) increases to about 0.5 per bit position per symbol. The advantage of proposed scheme is that QNSC makes use of basis with fewer bits for encryption/decryption.
This paper presents the security analysis on the quantum stream cipher so called Yuen-2000 protocol (or αηαηαη scheme) against the fast correlation attack, the typical attack on stream ciphers. Although a very simple experimental model of the quantum stream cipher without a random mapper may be decrypted in the information theoretic sense by the fast correlation algorithm, it is not a basic feature of Yuen 2000 protocol. In fact, we clarify that there exists a randomization scheme which attains the perfect correlation immunity against such attacks under an approximation. And in this scheme, the running key correlation from the second randomization that determines the mapping patterns is dismissed also by quantum noise. In such a case, any fast correlation attack does not work on the quantum stream cipher.