Digital chaotic physical layer encryption plays a crucial role in safeguarding data transmission security within data center interconnections (DCIs). However, existing encryption schemes remain vulnerable to active attacks, such as illegal optical access. To address these challenges, we propose a chaotic four-dimensional (4D) modulation scheme integrated with intrusion detection, which aims at enhancing the security of DCIs. The proposed scheme utilizes chaotic permutation and substitution encryption during the 4D modulation process, along with cross-polarization permutation to protect performance gains. Additionally, we propose a cost-effective and easily implementable intrusion detection method based on constellation same set ratio (CSSR). By dynamically adjusting the confidence region through CSSR analysis, the scheme enhances its robustness against noise interference. The proposed scheme is validated through 392 Gbit/s encrypted data transmission over an 80 km standard single-mode fiber, simulating attack scenarios including optical eavesdropping and illegal optical access. These results demonstrate that the proposed scheme achieves an information entropy of 3.999956, with a key space extending to 10360. The intrusion detection mechanism provides dynamic noise tolerance without requiring additional equipment, enabling the identification of illegal signals across various optical signal-to-noise ratios. This scheme provides a novel approach for resisting illegal optical access at the physical layer, with potential application in secure DCIs.
Digital chaotic physical layer encryption plays a crucial role in safeguarding data transmission security within data center interconnections (DCIs). However, existing encryption schemes remain vulnerable to active attacks, such as illegal optical access. To address these challenges, we propose a chaotic four-dimensional (4D) modulation scheme integrated with intrusion detection, which aims at enhancing the security of DCIs. The proposed scheme utilizes chaotic permutation and substitution encryption during the 4D modulation process, along with cross-polarization permutation to protect performance gains. Additionally, we propose a cost-effective and easily implementable intrusion detection method based on constellation same set ratio (CSSR). By dynamically adjusting the confidence region through CSSR analysis, the scheme enhances its robustness against noise interference. The proposed scheme is validated through 392 Gbit/s encrypted data transmission over an 80 km standard single-mode fiber, simulating attack scenarios including optical eavesdropping and illegal optical access. These results demonstrate that the proposed scheme achieves an information entropy of 3.999956, with a key space extending to 10360. The intrusion detection mechanism provides dynamic noise tolerance without requiring additional equipment, enabling the identification of illegal signals across various optical signal-to-noise ratios. This scheme provides a novel approach for resisting illegal optical access at the physical layer, with potential application in secure DCIs.
The network traffic of data centers (DCs) has increased unprecedentedly with the rapid development of digital economy. However, the data transmission faces security threats in the distributed optical interconnection and intensive interaction of DC networks. In this paper, we propose a chaotic phase noise-like encryption algorithm using geometric shaping (GS) for coherent DC interconnections (DCIs). A GS constellation is used to improve transmission performance, and it is combined with coherent equalization algorithms to improve security performance. Then, a chaotic encryption is designed based on phase noise-like transformation (PNLT). The data are effectively scrambled, and the confusion level of phase can be increased. Finally, 216 Gb/s 8-quadrature amplitude modulation (8-QAM) encrypted data are successfully verified on a 240 km transmission link of DCIs. The results show that this scheme can achieve a bit error rate (BER) performance gain of 1.1 dB and provide a highly compatible solution for realizing security enhanced DCIs.
Navigating the era of artificial intelligence and massive cloud computing presents a critical challenge: securing the explosive growth of data traffic across optical data center interconnects (DCIs). However, conventional physical-layer security (PLS) methods often treat encryption and authentication as disjointed modules, lacking the intelligent adaptability for dynamic channels. Here, we propose an intelligent intrinsic PLS framework to jointly execute identity authentication and data encryption in short-reach DCIs. Enabled by end-to-end deep learning, this scheme integrates a mixture density network (MDN) for dynamic channel condition with a constellation autoencoder. Utilizing chaotic index modulation, the system nonlinearly learns highly distinguishable geometric constellations and embeds watermarks into subcarrier indices for redundancy-free transmission. Through this intelligent mapping, security attributes are natively fused into the physical signals. We achieve a secure transmission using discrete multi-tone (DMT) signaling over a 10-km standard single-mode fiber (SSMF). The results demonstrate that our scheme dynamically optimizes watermark embedding, strongly thwarting unauthorized eavesdropping and robustly resisting impersonation attacks. This avant-garde paradigm offers a highly scalable and intelligent solution for secure next-generation optical DCI networks.
This paper proposes an odd-order quantum noise-like stream cipher scheme based on joint index modulation (JIM) constellation shaping. By utilizing subcarrier index modulation and dual-mode index techniques, additional information is transmitted through the combination distribution of silent subcarrier positions and constellation modes associated with subcarriers. An odd-order 9QAM signal is constructed, and by optimizing the index rule, constellation shaping is achieved while transmitting more information, increasing the distribution of constellation points within the signal. A 4D hyper-chaotic system is employed to implement multi-dimensional disturbances, including bitwise XOR of the original signal, subcarriers, symbols, and elevate the constellation order. Furthermore, the scheme performs upsampling on the chaotic system's initial values and actively introduces noise bits, which are appended to the initial signal as a basis state to enable key-accompanying transmission. Ultimately, the constellation-shaped 9QAM signal is escalated to a 576QAM signal with constellation shaping features. Experimental results demonstrate the successful transmission of a 2.94 Gb/s quantum noise stream signal over a 25 km single-mode fiber intensity modulation direct detection (IMDD) system. The experimental results show that the proposed JIM-576QAM1 signal provides a 0.7 dB gain at Forward error correction (FEC) = 3.8 × 10 −3 compared to random distribution of the two constellation modes. The proposed scheme maintains a bit error rate (BER) of 0 for key transmission, and abruptly increases to 0.5 in the event of misalignment, indicating a high sensitivity and accuracy of the system with respect to the key. At varying received optical power, the number of masked signal power remain consistent at 20480, and the detection failure probability stays around 1, demonstrating the stability and security of the proposed quantum noise stream encryption scheme. With a key space as large as 10 149 , the scheme can effectively counter brute-force attacks from unauthorized receivers. The proposed scheme exhibits high reliability and security, making it a promising candidate for future optical access applications.
Protecting the security of optical network is a major worldwide challenge. The conventional schemes for securing communications are based on cryptography at the MAC layer and its higher layers, which are facing a great threat with the development of quantum computers. Optical encryption is a promising way for building security on the physical layer of optical communications. In this work, we propose a novel optical encryption scheme for wavelength division multiplexing (WDM) fiber-optic communication systems, by utilizing the private chaotic phase scrambling. Secure transmission of 50 Gbps signal over 50-km standard single-mode fiber is experimentally and numerically demonstrated. The results show that the WDM signal is efficiently encrypted into a noise-like signal, due to the spectral broadening effect of chaotic phase scrambling. Since the processes of encryption and decryption are totally implemented in the optical domain, the proposed scheme can encrypt the entire network traffic with low latency and high speed. Moreover, the proposed encryption scheme is compatible with the existing WDM optical networks, and only one pair of encryption and decryption devices is sufficient to encrypt all WDM channels, thus the scheme can be easily implemented at low hardware cost.
In this paper, a scheme to realize encryption and digital identity authentication at the same time is proposed for enhancing the physical-layer security of point-to-point optical links (PPOL). Exploiting identity code encrypted by the key as authentication information effectively resists passive eavesdropping attacks in fingerprint authentication. The proposed scheme theoretically realizes secure key generation and distribution (SKGD) by phase noise estimation of the optical channel and the generation of identity codes with good randomness and unpredictability by the four-dimensional (4D) hyper-chaotic system. The local laser, erbium doped fiber amplifier (EDFA), and public channel provide the entropy source of uniqueness and randomness to extract symmetric key sequences for legitimate partners. The simulation conducted in a quadrature phase shift keying (QPSK) PPOL system over 100km standard single mode fiber verify successfully that 0.95Gbit/s error-free SKGD. The unpredictability and high sensitivity to the initial value and control parameters of the 4D hyper-chaotic system provide a huge space of ~10 125 for identity codes, which is sufficient to resist exhaustive attack. With the proposed scheme, the security level of key and identity can be increased markedly.
In recent years, the self-homodyne coherent (SHC) system and the constellation shaping (CS) technique have drawn considerable attention due to their abilities to further improve the transmission capacity for various scenarios. From the security point of view, the CS technique and the SHC infrastructure also provide new dimensions for encryption. We propose a high-security and reliable SHC system based on the CS technique and the digital chaos. With a four-dimensional hyperchaotic system, chaotic sequences are generated and used for the exclusive or operation, chaotic constant composition distribution matching, phase disturbance, and optical-layer time-delay disturbance. Moreover, 64-ary circular quadrature amplitude modulation (64CQAM) format is adopted for transmission due to its advantages of sensitivity to phase noise, immunity to conventional digital signal processing, and ability of time-mismatch masking, which is verified by simulation in a SHC system. Last, we conduct an experimental verification in a 20GBaud probabilistically shaped 64CQAM SHC system. Consequently, with a large-linewidth laser source, optical-layer security can be protected by time mismatches of tens of picoseconds. And the digital-layer security is protected by an enormous key space of 10 127 . The proposed scheme can provide reliable real-time encryption for the optical fiber transmission, serving as a potential candidate for the future high-capacity inter/intra-datacenter security interconnect.