Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE photonics journal

High-Speed Random-Channel Cryptography in Multimode Fibers

Rachel Sampson, He Wen, Bin Huang, Rodrigo Amezcua Correa, Yaron Bromberg, Hui W. Cao, Guifang Li

Published Jan 5, 2021• 14 citations
Publisher

Abstract

We propose and experimentally demonstrate high-speed operation of random-channel cryptography (RCC) in multimode fibers. RCC is a key generation and distribution method based on the random channel state of a multimode fiber and multi-dimension to single-dimension projection. The reciprocal intensity transmittance of the channel shared between the two legitimate users is used to generate and distribute correlated keys. In previous work, RCC's key rate-distance product was limited by the speed of light. In this work, we show that adding a fast modulator at one end of the channel decouples the key rate and distance, resulting in a significant improvement in the key rate-distance product, limited only by the fiber's modal dispersion. Error-free transmission at a key rate-distance product of 64.7 Mbps$ \times $12 km, which is seven orders of magnitude higher than the previous demonstration, was achieved. The proposed method's security arises from a fundamental asymmetry between the eavesdroppers’ and legitimate users’ measurement complexity.

DOI
10.1109/jphot.2021.3049253

Related papers

Key Distribution Using Scrambling of Digital Signals in Multimode Fiber

Binbin Chen, Yuanhong Liang, Rong Peng +1 more

We propose and verify a scheme that leverages the reciprocity and multipath scattering effects of multimode fibers to use them as scrambling devices. Each of the legitimate users possesses a segment of multimode fiber to scramble digital signals. When the scrambled digital signals are transmitted to a remote end through the transmission link, they need to pass through the multimode fiber at the remote end for a second scrambling to ensure security. Since the scrambling effect on the signal only exists in the multimode fiber, channel interference is compensated for, significantly enhancing transmission distance while maintaining high correlation. Additionally, the device’s security stems from its intrinsic state, as devices in different locations and environments exhibit varying states. The results show that even if an eavesdropper obtains a device with similar parameters, they cannot achieve the same sequence as the legitimate end-users. Ultimately, we achieved a key distribution rate of $0.18 \mathrm{Gbit} / \mathrm{s}$ using two segments of multimode fiber to scramble signals over a 50 km single-mode fiber.

International Conference on Communication Technology and Information Technology (ICCTIT)•Dec 27, 2024•0 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 Technology•Dec 8, 2020•46 citations

Remote key establishment by random mode mixing in multimode fibers and optical reciprocity

Yaron Bromberg, Brandon Redding, Sébastien M. Popoff +3 more

Disorder and scattering in photonic systems have long been considered a nuisance that should be circumvented. Recently, disorder has been harnessed for a rapidly growing number of applications, including imaging, sensing, and spectroscopy. The chaotic dynamics and extreme sensitivity to external perturbations make random media particularly well-suited for optical cryptography. However, using random media for distribution of secret keys between remote users still remains challenging since it requires the users have access to the same scattering sample. Here, we utilize random mode mixing in long multimode fibers to generate and distribute keys simultaneously. Fast fluctuations in fiber mode mixing provide the source of randomness for key generation, and optical reciprocity guarantees that the keys at the two ends of the fiber are identical. We experimentally demonstrate the scheme using classical light and off-the-shelf components, opening the door for a practically secure key establishment at the physical layer of fiber-optic networks.

arXiv:1506.07892•Optical Engineering•Jan 9, 2019•40 citations

High-Dimensional Quantum Cryptography with Hybrid Orbital-Angular-Momentum States through 25 km of Ring-Core Fiber: A Proof-of-Concept Demonstration

Qianke Wang, Fang‐Xiang Wang, Jun Liu +4 more

Quantum cryptography provides the inherent security for transmitting confidential information across free space or a fiber link. However, a high secure-key rate is still a challenge for a quantum-cryptography system. High-dimensional quantum cryptography, which can tolerate much higher channel noise, is a prospective way to share a higher secure-key rate between legitimate users, and has received substantial attention over the last decade. In particular, orbital angular momentum (OAM) can provide an abundant resource for high-dimensional quantum cryptography. Furthermore, combining spin angular momentum (SAM) with OAM can increase the encoding alphabet. Here we verify a prepare-and-measure quantum-cryptography scheme based on four-dimensional SAM-OAM hybrid states over kilometer-scale ring-core fibers. The measured quantum-bit error rates are $4.3\mathrm{%}$ for 4 km of fiber and $16.3\mathrm{%}$ for 25 km of fiber. The scheme simplifies the process of state preparation and measurement, with a compact and scalable setup.

Physical Review Applied•Jun 14, 2021•52 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 Letters•Dec 15, 2022•17 citations

Secure Key Generation and Distribution Using Polarization Dynamics in Fiber

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

Dynamic properties of optical signals in fiber channel provide a unique, random and reciprocal source for physical-layer secure key generation and distribution (SKGD). In this paper, an inherent physical-layer SKGD scheme is proposed and demonstrated, where the random source is originated from the dynamic fluctuation of the instant state of polarization (SOP) of optical signals in fiber. Due to the channel reciprocity, highly-correlated fluctuation of Stokes parameter of SOP is shared between the legal partners, where an error-free key generation rate (KGR) of 196-bit/s is successfully demonstrated over 25-km standard single-mode fiber (SSMF). In addition, an active polarization scrambler is deployed in fiber to increase the KGR, where an error-free KGR of 200-kbit/s is achieved.

International Conference on Transparent Optical Networks•Jul 1, 2020•4 citations
We propose and experimentally demonstrate high-speed operation of random-channel cryptography (RCC) in multimode fibers. RCC is a key generation and distribution method based on the random channel state of a multimode fiber and multi-dimension to single-dimension projection. The reciprocal intensity transmittance of the channel shared between the two legitimate users is used to generate and distribute correlated keys. In previous work, RCC's key rate-distance product was limited by the speed of light. In this work, we show that adding a fast modulator at one end of the channel decouples the key rate and distance, resulting in a significant improvement in the key rate-distance product, limited only by the fiber's modal dispersion. Error-free transmission at a key rate-distance product of 64.7 Mbps×\times×12 km, which is seven orders of magnitude higher than the previous demonstration, was achieved. The proposed method's security arises from a fundamental asymmetry between the eavesdroppers’ and legitimate users’ measurement complexity.
We propose and verify a scheme that leverages the reciprocity and multipath scattering effects of multimode fibers to use them as scrambling devices. Each of the legitimate users possesses a segment of multimode fiber to scramble digital signals. When the scrambled digital signals are transmitted to a remote end through the transmission link, they need to pass through the multimode fiber at the remote end for a second scrambling to ensure security. Since the scrambling effect on the signal only exists in the multimode fiber, channel interference is compensated for, significantly enhancing transmission distance while maintaining high correlation. Additionally, the device’s security stems from its intrinsic state, as devices in different locations and environments exhibit varying states. The results show that even if an eavesdropper obtains a device with similar parameters, they cannot achieve the same sequence as the legitimate end-users. Ultimately, we achieved a key distribution rate of 0.18Gbit/s0.18 \mathrm{Gbit} / \mathrm{s}0.18Gbit/s using two segments of multimode fiber to scramble signals over a 50 km single-mode fiber.
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.
Disorder and scattering in photonic systems have long been considered a nuisance that should be circumvented. Recently, disorder has been harnessed for a rapidly growing number of applications, including imaging, sensing, and spectroscopy. The chaotic dynamics and extreme sensitivity to external perturbations make random media particularly well-suited for optical cryptography. However, using random media for distribution of secret keys between remote users still remains challenging since it requires the users have access to the same scattering sample. Here, we utilize random mode mixing in long multimode fibers to generate and distribute keys simultaneously. Fast fluctuations in fiber mode mixing provide the source of randomness for key generation, and optical reciprocity guarantees that the keys at the two ends of the fiber are identical. We experimentally demonstrate the scheme using classical light and off-the-shelf components, opening the door for a practically secure key establishment at the physical layer of fiber-optic networks.
Quantum cryptography provides the inherent security for transmitting confidential information across free space or a fiber link. However, a high secure-key rate is still a challenge for a quantum-cryptography system. High-dimensional quantum cryptography, which can tolerate much higher channel noise, is a prospective way to share a higher secure-key rate between legitimate users, and has received substantial attention over the last decade. In particular, orbital angular momentum (OAM) can provide an abundant resource for high-dimensional quantum cryptography. Furthermore, combining spin angular momentum (SAM) with OAM can increase the encoding alphabet. Here we verify a prepare-and-measure quantum-cryptography scheme based on four-dimensional SAM-OAM hybrid states over kilometer-scale ring-core fibers. The measured quantum-bit error rates are $4.3\mathrm{%}$ for 4 km of fiber and $16.3\mathrm{%}$ for 25 km of fiber. The scheme simplifies the process of state preparation and measurement, with a compact and scalable setup.
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.
Dynamic properties of optical signals in fiber channel provide a unique, random and reciprocal source for physical-layer secure key generation and distribution (SKGD). In this paper, an inherent physical-layer SKGD scheme is proposed and demonstrated, where the random source is originated from the dynamic fluctuation of the instant state of polarization (SOP) of optical signals in fiber. Due to the channel reciprocity, highly-correlated fluctuation of Stokes parameter of SOP is shared between the legal partners, where an error-free key generation rate (KGR) of 196-bit/s is successfully demonstrated over 25-km standard single-mode fiber (SSMF). In addition, an active polarization scrambler is deployed in fiber to increase the KGR, where an error-free KGR of 200-kbit/s is achieved.