Authentication of persons and objects is a crucial aspect of security. We experimentally demonstrate quantum-secure authentication (QSA) of a classical multiple-scattering key. The key is authenticated by illuminating it with a light pulse containing fewer photons than spatial degrees of freedom and verifying the spatial shape of the reflected light. Quantum-physical principles forbid an attacker to fully characterize the incident light pulse. Therefore, he cannot emulate the key by digitally constructing the expected optical response, even if all information about the key is publicly known. QSA uses a key that cannot be copied due to technological limitations and is quantum-secure against digital emulation. Moreover, QSA does not depend on secrecy of stored data, does not depend on unproven mathematical assumptions, and is straightforward to implement with current technology.

Quantum-secure authentication of a physical unclonable key

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.

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

The unique and random physical-layer properties of optical fiber channels have been exploited for a simple and cost-effective secure key generation and distribution (SKGD) However, state-of-the-art SKGD approaches focused mainly on initial key extraction, while the post-processing protocol has to be explored to guarantee error-free operation, effective key generation rate (KGR) and high key secrecy Here we propose a full post-processing protocol for SKGD in fiber networks A lossy quantizer is optimized to achieve the trade-off between the KGR and key disagreement rate The distributed source coding based information reconciliation is used to remove quantization errors The privacy amplification is applied to improve the randomness and secrecy of the generated key using hashing functions The post-processing protocol provides a SKGD solution of error-free, high randomness and high secrecy in fiber networks

Post-Processing Protocol for Physical-Layer Key Generation and Distribution in Fiber Networks

In recent years, neural networks and cryptographic schemes have come together in war and peace; a cross-impact that forms a dichotomy deserving a comprehensive review study. Neural networks can be used against cryptosystems; they can play roles in cryptanalysis and attacks against encryption algorithms and encrypted data. This side of the dichotomy can be interpreted as a war declared by neural networks. On the other hand, neural networks and cryptographic algorithms can mutually support each other. Neural networks can help improve the performance and the security of cryptosystems, and encryption techniques can support the confidentiality of neural networks. The latter side of the dichotomy can be referred to as the peace. There are, to the best of our knowledge, no current surveys that take a comprehensive look at the many ways neural networks are currently interacting with cryptography. This survey aims to fill that niche by providing an overview on the state of the cross-impact between neural networks and cryptography systems. To this end, this paper will highlight the current areas where progress is being made as well as the aspects where there is room for future research to be conducted.

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The Dichotomy of Neural Networks and Cryptography: War and Peace

We propose and verify a simple precoding-less scheme to generate quadrature phase shift keying (QPSK) modulated vector millimeter-wave signal based on a single phase modulator (PM). The electrical vector data is first up-converted to achieve a 12 GHz radio frequency (RF) vector signal, then the RF vector signal is added with the other unmodulated RF source at 18 GHz, of which the generations are enabled by a digital signal processing (DSP). Next, the coupled RF source drive a PM to generate multi-frequency optical sidebands. A wavelength selective switch is adopted to pick out two optical sidebands at different frequencies which will beat frequency in the photo-detector (PD). In this scheme, we set up a simulation platform to generate 48 GHz QPSK modulated vector millimeter-wave signals and analyzed the performance. The results show when the input power for the generated 1-Gbaud/s vector millimeter-wave into PD is not less than -18 dBm, the bit-error ratio can be below 3.8 × 10 - 3 , which demonstrate that the generated vector millimeter-wave signal enabled by our proposed scheme can work well.

A simple photonic precoding-less scheme for vector millimeter-wave signal generation based on a single phase modulator

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/ $\text{s}\cdot $ 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.

16 QAM Quantum Noise Stream Cipher Coherent Transmission Over 300 km Without Intermediate Amplifier

Physical layer authentication is an important way to ensure the security of optical communication network. We hereby propose a scheme to realize it by measuring the variation of the bit error rate (BER) on both sides of communication. In this scheme, the legitimacy of the receiver is identified by analyzing the BER variation of the optical fiber loop based on the short-term correlation of the channels. We then simulate a 16 PSK optical transmission system with intensity modulation direct detection-orthogonal frequency division multiplexing (IMDD-OFDM). The authentication effect is analyzed in the case of disturbance and beam split, as well as replacement of optical fiber channels caused by eavesdropper (Eve). The results show that this scheme is sensitive to the three kinds of attacks. A high probability of detection (PD) and a low false alarm rate (FAR) can be obtained. The experimental results show that with the increase of the frequency test, PD and FAR tend to be stable, and the authentication effect is better with the accuracy rate 100%.

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Physical Layer Authentication Based on BER Measurement of Optical Fiber Channel

We propose a long-haul and high-speed key distribution based on one-way non-dual arbitrary basis transformation in optical fiber link. The key distribution rate of 277 Kbit/s with free key error rate is demonstrated over 300km.

Long-Haul and High-Speed Key Distribution Based on One-Way Non-Dual Arbitrary Basis Transformation in Optical Fiber Link

This paper first introduces information reconciliation into physical layer secret key distribution within optical communication. The final secret key rate can reach 352.5 kbit/s and the key consistency rate achieves 100% in 300 km experiment.

Experiment Demonstration of Physical Layer Secret Key Distribution with Information Reconciliation in Digital Coherent Optical OFDM System

We propose a survival life time-based key distribution scheme with Y-00 protocol in optical fiber physical layer. Simulation results shows that with the proposed scheme, the bit-error rate of keys can reach 1.3%.

Chao Lei

Papers

16 QAM Quantum Noise Stream Cipher Coherent Transmission Over 300 km Without Intermediate Amplifier

Physical Layer Authentication Based on BER Measurement of Optical Fiber Channel

Long-Haul and High-Speed Key Distribution Based on One-Way Non-Dual Arbitrary Basis Transformation in Optical Fiber Link

Experiment Demonstration of Physical Layer Secret Key Distribution with Information Reconciliation in Digital Coherent Optical OFDM System

Key Distribution Based on Survival Life Time with Y-00 Protocol in Optical Fiber Link