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.
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.
This paper proposes a novel key distribution system based on the measurement of the bit error rate (BER) in a fiber channel. By carrying out the loopback BER measurement at both the transmitting and the receiving end, the BER is quantified and codified to generate consistency keys. Alice and Bob respectively encrypt the signal with the help of the public key base at the transmitting end. At the receiving end the data are decrypted and then the BER is measured. The security of generated keys in the system is enhanced by the use of the encryption base and the randomness of the channel. Additionally, noise sources are added to the channel so that the random noise conceals signals and Eve cannot eavesdrop the useful information in it. Due to the randomness of the channel noise, the generated keys have good randomness. This system at a high key generation rate is compatible with the existing communication device and its measurement is simple. The 10G bit/s-200 km coherent optical communication system is used to measure the BER of the security feature information of the extracted channel. The experimental results show that the key distribution system obtains a consistency rate of 98% with the key generation rate 2 Mbps, both of which have been significantly improved.
With the wide application of large-capacity and high-speed optical networks, its security has become a current research focus. Due to the limitations of traditional key distribution and encryption schemes, this paper proposes an innovative key distribution and encryption control scheme based on physical layer channel feature extraction and analysis. First of all, the transceiver terminal extracts the physical characteristics of the fiber channel separately, and generates a consensus key through quantization coding. Second, use the generated key base to encrypt the transmission sequence, map the Quadrature Phase Shift Keying (QPSK) signal to the high-order 1024×1024-QAM signal, and use the noise stream to perform the high-order QAM. The signal is flooded. The system utilizes channel non-replication and randomness of channel noise, the security and randomness of the key are good, and the key formation rate is high and the key generation equipment is simple. The system uses high-order QAM modulation, which increases the security of the system. The experimental results show that the coding rate of the key generated by the system reaches 400kb/s, and the coding performance of the key is better; the operating key is generated by the key base extension, which has strong anti-interception ability; the system has a low bit error rate and secure transmission Good performance.
This paper proposes and experimentally demonstrates an error-free secure key generation and distribution (SKGD) scheme in classical optical fiber link by exploiting Stokes parameters (SPs) of the state of polarization (SOP). Due to the unique birefringence distribution of the optical fiber channel, random but high-correlated SPs are shared between Alice and Bob. The dynamic SPs are also affected by the time-varying environmental factors, providing the source of randomness for the secret key extraction. As a proof of concept, key generation rate (KGR) of 213-bits/s is successfully demonstrated over 25-km standard single-mode fiber (SSMF). The error-free SKGD is realized in fiber channel using the information reconciliation (IR) technology, where Bose-Chaudhuri-Hocquenghem (BCH) codes are applied. Due to the channel uniqueness and the high-sensitivity to the initial SOP of optical signals, high-level security is provided by the proposed scheme, which is analyzed and verified against the possible fiber-tapping attacks. Moreover, the proposed SKGD scheme offers additional benefits such as simple structure, low cost, and suitablity for long-haul transmission.
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.
This paper proposes a key distribution system based on short-time correlation of optical fiber channels. The communicating parties adopt the odd-even interleaved data transmission method to send binary random number sequences to each other. Taking advantage of the close arrangement of data parity, the data obtained by the communicating parties has short-time correlation characteristics. By analyzing the bit error rate (BER) of the transmitted data, quantizing and encoding the BER, and executing the key negotiation protocol, the short-time correlation characteristics of the channel can be extracted, and the original key with good consistency can be obtained. The experimental results show that when the optical fiber length between Alice and Bob is 40 km, the signal is modulated by Quadrature Phase Shift Keying with Orthogonal Frequency Division Multiplexing (QPSK-OFDM), the signal transmission rate is 1 Gbit/s, and the channel BER is about 0.2, the change trend of the BER sampling values measured by Alice and Bob has good consistency. After the BER sampling value is quantized and encoded, the original key with a consistency rate of 95.93% is finally obtained. We further analyze the impact of the quantization threshold on the number of keys and key error rate under different BER. When L = 50, L×ασ = 2.5, and BER = 0.12, 146 keys can be obtained, and the key error rate is 0, which is the best key generation effect.
To address the urgent demand for secure optical fiber communication, a novel dual independent key generation and distribution scheme for Optical Network Physical Layer Security is proposed for the first time. End-to-end (E2E) learning with a Transformer algorithm featuring adaptive positional encoding is introduced to accurately model coherent fiber transmission systems, achieving an R-squared value exceeding 0.95 for waveform fitting and data distribution. The error vector phase (EVP) and amplitude noise (AN) of the E2E system are utilized to comprehensively characterize channel uniqueness, reducing system reconstruction risks while serving as sources for highly random key sequences for legitimate parties. Key consistency stems from channel reciprocity and precise E2E modeling, with feasibility analyzed across diverse link conditions. Leveraging the fact that eavesdroppers cannot access the system's full lifecycle data, keys are extracted from outputs of transfer learning (TL)-updated E2E models to enhance security. Security analysis under various eavesdropping scenarios demonstrates resistance to attacks. Experimental results show that, with FPGA-implemented post-processing, error-free key distribution is achieved over 120 km SSMF at EVP and AN key rates of 306.74 Mbps and 521.82 Mbps, respectively.