Quantum noise stream cipher where encrypted signals are masked by quantum noise and ASE noise provides a physical layer of security. It requires the transmitter and the receiver to share a stream ...cipher that is generated from a PRNG. Yet a correlation attack threatens its security due to the mathematical properties of PRNG. This paper discusses the security of QNSC system under correlation attacks. Our experiment results find that the security of the whole system depends on the cycle to refresh the seed key and the correlation between the incepted running key, original running key, and seed key. Furthermore, it is important to provide security for the QNSC system by maintaining low optical power. Besides, this new analytical method provides quantitative security analysis for a QNSC system under a correlation attack.
With the increase in the popularity of cloud computing and big data applications, the amount of sensitive data transmitted through optical networks has increased dramatically. Furthermore, optical ...transmission systems face various security risks at the physical level. We propose a novel key distribution scheme based on signal-to-noise ratio (SNR) measurements to extract the fingerprint of the fiber channel and improve the physical level of security. The SNR varies with time because the fiber channel is affected by many physical characteristics, such as dispersion, polarization, scattering, and amplifier noise. The extracted SNR of the optical fiber channel can be used as the basis of key generation. Alice and Bob can obtain channel characteristics by measuring the SNR of the optical fiber channel and generate the consistent key by quantization coding. The security and consistency of the key are guaranteed by the randomness and reciprocity of the channel. The simulation results show that the key generation rate (KGR) can reach 25 kbps, the key consistency rate (KCR) can reach 98% after key post-processing, and the error probability of Eve’s key is ~50%. In the proposed scheme, the equipment used is simple and compatible with existing optic fiber links.
Quantum noise stream cipher based on quadrature-amplitude-modulation (QAM/QNSC) is a kind of physical layer encryption technology. However, the additional encryption penalty will significantly affect ...the practical deployment of QNSC, especially in the high capacity and long-haul transmission system. With our research, the encryption process of QAM/QNSC degrades the transmission performance of plaintext information. In this paper, we quantitatively analyze the encryption penalty of QAM/QNSC based on the proposed concept of effective minimum Euclidean distance. We calculate the theoretical signal-to-noise ratio sensitivity and encryption penalty of QAM/QNSC signals. A modified feedforward pilot-aided two-stage carrier phase recovery scheme is used to reduce the effect of laser phase noise and the encryption penalty. Experimental results achieve single-channel 205.9 Gbit/s 640km transmission with single carrier polarization-diversity-multiplexing 16-QAM/QNSC signal.
A quantum noise stream cipher scheme (QNSC) based on triangular quadrature amplitude modulation (TQAM) and the secret probabilistic shaping (SPS) is studied. Compared with rectangular quadrature ...amplitude modulation (QAM), TQAM is a more compact symmetrical structure, which results in better transmission performance and greater noise masking number. Then, SPS is realized, where the probabilistic shaping information as the secret key is masked into noise and transmitted with the encrypted signal simultaneously. The combination of SPS and QNSC makes it impossible for an attacker to obtain the ciphertext, which enhances the security of QNSC scheme without introducing additional key. TQAM and probabilistic shaping improve the transmission performance of QNSC scheme. Under 7% forward error correction (FEC) threshold in back-to-back system, compared with QAM/QNSC systems, TQAM/QNSC provides an OSNR gain of ∼ 0.6 dB, and SPS-TQAM/QNSC provides an OSNR gain of ∼ 1.2 dB. The proposed scheme is demonstrated with the net data rate of 34.28 Gbit/s over 140 km single-span standard single mode fiber.
Quantum noise stream cipher based on quadrature-amplitude-modulation (QAM/QNSC) is a kind of physical layer encryption technology. However, the additional encryption penalty will significantly affect ...the practical deployment of QNSC, especially in the high capacity and long-haul transmission system. With our research, the encryption process of QAM/QNSC degrades the transmission performance of plaintext information. In this paper, we quantitatively analyze the encryption penalty of QAM/QNSC based on the proposed concept of effective minimum Euclidean distance. We calculate the theoretical signal-to-noise ratio sensitivity and encryption penalty of QAM/QNSC signals. A modified feedforward pilot-aided two-stage carrier phase recovery scheme is used to reduce the effect of laser phase noise and the encryption penalty. Experimental results achieve single-channel 205.9 Gbit/s 640km transmission with single carrier polarization-diversity-multiplexing 16-QAM/QNSC signal.
In the quantum noise stream cipher (QNSC) system, the low-order plaintext is encrypted by pre-shared keys into high-order ciphertext. However, high-speed optical communication systems have a huge ...demand for pre-shared keys. On the other hand, the separation of the secure communications sub-system from the secure key distribution (SKD) sub-system increases potential security risks and introduces additional resources overhead. In this letter, we propose an artificial amplitude noise-based SKD scheme (AAN-SKD) in QAM/QNSC to generate secret key for legal parties accordingly. The two orthogonal PAM symbols are superimposed to generate QAM symbols. Thus, the AAN-SKD can also be implemented in PAM modulation. In addition, the data transmission and AAN-SKD are completed in the same channel. Experimental results indicate that the key generation rate and key consistency ratio of the proposed scheme can reach 188.22 Mbit/s and 91%, respectively. Compared with quantum key distribution, the AAN-SKD has the advantage of lower cost, better compatibility, and a higher key rate.
•This paper proposes a fingerprint SNR authentication method based on the physical layer of optical communication.•In the scheme, the authenticator Alice measures SNR through loopback and the dynamic ...TSNR is calculate.•The simulation result shows that when PPD is near 100%, PFAR close to 0, so PPD should be higher and PFAR should be smaller.•To improve the effect of authentication, the threshold is set as η > 0.•We can adjust the threshold to find the best Y value for the best authentication results.
In order to improve the physical layer authentication security, a novel scheme based on the dynamic characteristics of optical channels is proposed. By constructing a loop-back fiber link, the authenticating party can extract the dynamic characteristics of the entire fiber channel. By calculating the rate of the change of signal-to-noise ratio (SNR) with the methods such as channel feature extraction and quantitative noise reduction, the SNR as the key index of optical fiber physical layer authentication can accurately reflect the dynamic characteristics of the channel. In this article, Eve performs simulated attacks on the system from different distances, splitting ratios, and introducing additional noise to test the security authentication effect. The results show that by setting an appropriate threshold, the authentication effect is good with the detection probability PPD close to 100% and the false alarm rate PFAR close to 0. At the same time, the convenience and high speed of measuring SNR means its high popularization and economic benefits.
•The proposed scheme is practical and compatible, which does not require extra dynamic parameters and physical devices.•Compared with existing SKGD schemes, the proposed proposal has higher key ...generation rate or longer key distribution distance.•When the agreement data is placed at the 7th bit of the symbol, the highest bit can be used for transmission, so that the key distribution and secure transmission can be integrated.•The key generated by the proposed scheme has true randomness and no relationship with the pre-shared information.•The randomness of noise, quantum stream cipher, and added Gaussian white noise at receivers collectively ensure the security of the proposed scheme.•Seed keys can be generated continuously by sharing a small amount of information only once.
Considering the key demand in the secure optical fiber communication, a key generation and distribution scheme based on random noise variances is proposed. The noise of optical communication systems is inevitable due to the influence of various factors. The additive noise that cannot be eliminated is random after digital signal processing, which ensures the randomness of the key. However, the range of system noise variances is small and the noise of links is exposed. A random Gaussian white noise is added at receivers, which increases the noise fluctuation and enhances security. Legitimate parties obtain secure keys by calculating the data inconsistency rate, where the consistency comes from the correlation of noise variances in adjacent time slots over a period of time. Experimental results demonstrate that the error-free key is obtained with the key generation rate of 1.6 Mbit/s over 105 km standard single-mode fiber. Moreover, the security analysis shows that the proposed key generation and distribution scheme can resist fiber-tapping attacks.
We propose an efficient correlation attack based on low-order demodulation to recover the seed keys in QNSC. Experiment results prove its high success possibility and low computational complexity in ...300km QAM/QNSC transmission.
We propose a physical layer key distribution scheme based on signal hiding and concatenated coding. Experimental results demonstrate that an error-free key can be obtained with the key generation ...rate of 2.5 Gbps over the 80-km standard single-mode fiber.
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