Journal of Lightwave Technology

Coexistence of High-Speed Physical-Layer Key Distribution and Secure Data Transmission in Fiber

Xinran Huang, Xinyong Peng, Liuming Zhang, Zhi Chai, Mingye Li, Weisheng Hu, Xuelin Yang

Published Sep 18, 2023• 10 citations

Abstract

Physical-layer secure key distribution (PLSKD) exploiting channel reciprocity and randomness is promising for data security enhancement in fiber, offering an endogenous high key generation rate (KGR) up to Gb/s. The PLSKD provides the integration possibility of key generation and data transmission within the same fiber channel. The coexistence schemes of PLSKD and secure data transmission in fibers are proposed using wavelength division multiplexing (WDM), and full-duplex transmission at the same wavelength. The coexistence schemes are experimentally demonstrated with a 3.4 and 3.25 Gb/s PLSKD, where the encrypted data rate is 15.7 Gb/s, over a 20 km standard single-mode fiber (SSMF) using WDM or full-duplex respectively. The effects of channel spacing using WDM and trade-offs between PLSKD and secure data transmission using full-duplex are fully analyzed. The proposed secure data transmission with PLSKD is classical and fully compatible with current fiber infrastructures.

DOI: 10.1109/jlt.2023.3316270

Related papers

Unidirectional physical layer secure key distribution in a fiber channel assisted by neural networks

Liuming Zhang, Xinran Huang, Zhi Chai +3 more

Physical layer secure key distribution (PLSKD) in fiber networks provides high-level security originating from the channel uniqueness, while the channel reciprocity is shared between the legal users via bidirectional transmission. To ensure the key consistency, perfect wideband bidirectional optical devices are required for high-speed PLSKD. Here, we propose and demonstrate a unidirectional PLSKD scheme, where the channel reciprocity is reproduced by neural networks (NNs) so that highly correlated key waveforms are generated and shared between the legal users. Experimental results show that an error-free key generation rate (KGR) of 3.8 Gb/s with excellent randomness is achieved for an 11-km standard single-mode fiber (SSMF) channel. The proposed scheme alleviates the stringent requirement of bidirectional channel transmission in high-speed PLSKD and enables the integration of PLSKD and data transmission in the same fiber channel.

Optics LettersJul 20, 202217 citations

Wavelength dependence of fiber channel reciprocity for bidirectional physical-layer key distribution

Xinran Huang, Yunhao Xie, Liuming Zhang +6 more

To share the reciprocity of a single fiber channel in physical-layer secure key distribution (PLSKD), the bidirectional same wavelength (B-SW) transmission system is generally applied. However, the elastic Rayleigh backscattering noise severely degrades key performance after long fiber transmission. Here, the feasibility of a bidirectional wavelength division multiplexing (B-WDM) transmission in a single fiber for high-speed long-range PLSKD is verified, where the wavelength dependence of fiber channel reciprocity is evaluated. PLSKD based on B-WDM in one standard 100 GHz WDM channel is demonstrated, offering a key generation rate of 4.8 Gbps over a 200 km fiber link, providing a 200% increment in terms of key generation rate (KGR) compared with B-SW transmission.

Optics LettersApr 10, 20253 citations

10 Gb/s physical-layer key distribution in fiber using amplified spontaneous emission

Xinran Huang, Liuming Zhang, Zhi Chai +4 more

High-speed physical-layer secure key generation and distribution (SKGD) schemes via channel reciprocity are achieved using external electro-optical modulation or random source distribution via additional fiber links. Here, we propose and demonstrate an SKGD scheme using the fluctuation of polarization states from an amplified spontaneous emission (ASE) source, without any external electro-optical modulation or additional fiber link. Experimentally, an error-free key generation rate (KGR) of 10.1 Gb/s is achieved over a 10-km standard single-mode fiber (SSMF), with true randomness originating from ASE. Moreover, the single fiber channel can be shared for SKGD as well as data transmission, allowing the integration of the proposed SKGD with the deployed fiber infrastructure.

Optics LettersDec 15, 202217 citations

A 300 km fiber channel mapping using neural networks for Gb/s physical-layer key distribution

Xinran Huang, Xinyong Peng, Liuming Zhang +2 more

Physical-layer secure key distribution (PLSKD) generally acquires highly correlated entropy sources via bidirectional transmission to share the channel reciprocity. For long-haul fiber links, the non-negligible backscattering noise (BSN) and the challenge of bidirectional optical amplification degrade the key generation performances. Since the channel reciprocity can be precisely mapped using neural networks (NNs), unidirectional PLSKD provides a feasible PLSKD for longer fiber links. Here, a final error-free key generation rate (KGR) in unidirectional PLSKD of 3.07 Gb/s is demonstrated over a 300 km fiber link using NNs. Moreover, the channel mapping is analyzed in terms of fiber distance, chromatic dispersion, the nonlinearity of random source, and BSN.

Optics LettersDec 6, 202310 citations

284.8-Mb/s Physical-Layer Cryptographic Key Generation and Distribution in Fiber Networks

Adnan A. E. Hajomer, Liuming Zhang, Xuelin Yang +1 more

Key distribution is a major challenge of secure communication. Computational approaches to key distribution are breached by quantum algorithms, while quantum key distribution (QKD) is an expensive, slow, and sophisticated solution. Secure key generation and distribution from unpredictable and inherent physical-layer properties of optical fiber channel is a classical, simple and cost-effective solution. However, the quasi-static nature of fiber channels dramatically limits the available key generation rate (KGR) to the order of ~kbit/s. Here we effectively accelerate the KGR by six orders of magnitude using a developed high-speed chaotic polarization scrambler (CPS) driven by digital chaos in fiber channels. An error-free KGR of 284.8 Mbit/s is experimentally demonstrated over a 24 km standard single-mode fiber (SSMF), where the generated key passes the random test suite. Moreover, we fully analyze the security mechanism and find that a strong asymmetry exists between legal and illegal users, ensuring a high-level of security against potential fiber-tapping attacks. This scheme provides a major step towards the practical implementation of the “one-time-pad” in secure data transmission over fiber networks.

Journal of Lightwave TechnologyDec 8, 202046 citations

2.7 Gb/s Secure Key Generation and Distribution Using Bidirectional Polarization Scrambler in Fiber

Liuming Zhang, Adnan A. E. Hajomer, Weisheng Hu +1 more

A physical-layer secure key generation and distribution (SKGD) scheme in classical fiber channel is proposed and demonstrated using a bidirectional wide-band polarization scrambler (WBPS), to alter rapidly and symmetrically the state of polarization (SOP) for the two counter-propagating optical signals in fiber. Due to the optical channel reciprocity, highly-consistent key bits can be extracted from the correlated SOP fluctuations, while the key secrecy is ensured by the fiber channel uniqueness. A final key generation rate (KGR) of 2.7 Gb/s is demonstrated over 10 km single mode fiber (SMF), where error-free and true randomness of the generated key are achieved after post-processing. The obtained KGR at Gb/s makes a further step towards the implementation of one-time-pad data encryption with perfect secrecy in fiber networks.

IEEE Photonics Technology LettersFeb 11, 202136 citations