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.
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.
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.
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.
In this Letter, we propose a secure orthogonal frequency division multiplexing (OFDM) transmission scheme based on chaotic encryption and noise-masking key distribution. With the implementation of a three-dimensional digital chaotic system, the security performance is effectively enhanced by scrambling the phase, symbol, and subcarrier frequency of the OFDM signal. The proposed noise-masking key distribution can mask the key information of the chaotic system into noise and transmit it with the chaotic encrypted signal simultaneously. By this mechanism, the legal receiver can realize uninterrupted authentication and decryption even if the key is constantly updated. Transmission of a 62.2-Gb/s quadrature phase shift keying (QPSK) and 124.4-Gb/s 16 quadrature amplitude modulation (16QAM) OFDM signal over a 2-km 7-core fiber using the proposed scheme is experimentally demonstrated. The results show that the proposed scheme can realize security enhancement and cost-effective key distribution without significant bit error ratio (BER) performance degradation.
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.
In this article, we propose a high-security transmission scheme of power division 3-D carrier-less amplitude and phase (PD-3D-CAP) based on polling-permutation encryption and noise masking key distribution. By implementing the 6D Lorenz digital chaotic system, we scramble the 3D-CAP signal, effectively enhancing the security performance of the system. In our scheme, the proposed noise-masking key distribution can be considered noise-like and transmitted along with the chaotic encrypted signal in the channel. It is important to note that our mechanism also enables uninterrupted authentication and decryption at the receiver to handle continuous key updates. We experimentally demonstrate the transmission of a 12.67 Gb/s 3D-CAP signal over a 2 km 7-core fiber using the proposed scheme. The scheme allows for simultaneous key transmission without a significant increase in the bit error rate. Additionally, we compare the performance of the PD-3D-CAP scheme to that of the PD-2D-CAP scheme, and observe a sensitivity gain of 0.4 dB with the proposed PD-3D-CAP scheme.
This article proposes a redundancy-free multiple phase-offset based key distribution (MPO-KD) scheme for solving the physical-layer session key agreement in optical data center interconnections (DCIs). High-dimensional chaotic encryption is a promising technology expected to provide better security for massive-scale data transmission in DCIs. Considering the huge key space introduced by hyper-chaos, the proposed scheme converts digital keys into the phase of quadrature amplitude modulation (QAM) symbols by actively introducing controllable offsets. The solution of offset factor space is modeled as a multi-objective optimization problem for improving the key distribution performance. The Pareto optimal set is obtained using the non-dominated sorting moth-flame optimization (NS-MFO) algorithm. The two-channel 140 Gb/s 16-QAM, 176 Gb/s 32-QAM and 210 Gb/s 64-QAM orthogonal frequency division multiplexing (OFDM) signal transmissions are successfully demonstrated. The results indicate that this scheme achieves error-free key distribution without degrading system performance, which supports an expandable large key space and has good compatibility with various encryption algorithms.