International Conference on Optical Communications and Networks (ICOCN)
Physical layer encryption for polarization division multiplexing coherent optical communication system based on the rotation of the state of polarization
In this paper, we propose an optical physical layer encryption method to encrypt the signal of polarization division multiplexing (PDM) coherent optical communication system by introducing an artificially controlled fast rotation of the state of polarization (RSOP) into the signal. Simulations conducted in a 40 Gbps PDM-QPSK system show that the authorized user can successfully decrypt the received signal, while the eavesdroppers cannot derive useful information with bit error rates (BER) at 0.38~0.48, which shows that the method effectively improves the security of the system.
In this paper, we propose an optical physical layer encryption method to encrypt the signal of polarization division multiplexing (PDM) coherent optical communication system by introducing an artificially controlled fast rotation of the state of polarization (RSOP) into the signal. Simulations conducted in a 40 Gbps PDM-QPSK system show that the authorized user can successfully decrypt the received signal, while the eavesdroppers cannot derive useful information with bit error rates (BER) at 0.38~0.48, which shows that the method effectively improves the security of the system.
In this paper, a security enhanced physical layer encryption scheme is proposed for coherent optical polarization division multiplexing (PDM) systems. The concept of a digital optical polarization scrambler (DOPS) is introduced to apply high speed rotation of state of polarization (RSOP) to the transmitted signal, which enables encryption based on polarization perturbations and offers superior flexibility in polarization management. By utilizing different combinations of digital polarization device matrices and adjusting their key parameters, four encryption modes are designed. The proposed encryption scheme is successfully implemented in a PDM-QPSK system at the data rate of 32 Gbps. Experimental results demonstrate that authorized users can successfully decrypt the received signal, while the eavesdroppers cannot derive useful information with a bit error rate (BER) at approximately 0.5. To enhance system security, a 5-D chaotic system is introduced with superior properties of high sensitivity to initial values and improved uniform distribution, which guarantees the large entropy and further the system’s security. This scheme can effectively prevent against brute attacks with the expanded key space of 10 60 .
Abstract—The paper proposes an optical physical layer encryption scheme based on the combination of similar rotation of the state of polarization (SRSOP) and a six-dimensional (6-D) hyperchaotic system. By introducing similar polarization state rotation to disturb vector data at the transmitting end, the security of optical transmission systems can be effectively enhanced In addition, the data perturbation of polarization state rotation, combined with the 6D hyperchaotic system with unpredictability and sensitivity, can extend the key space of the encryption scheme to 10180, making it resistant to brute force attacks. The encryption process of this scheme is as follows: Firstly, the chaotic sequences generated by the 6D hyperchaotic system were used to encrypt various parameters in the polarization encryption matrix, and then these parameters were used to generate the corresponding polarization encryption matrix. Finally, the encryption matrix was used to perturb the data to be sent. The scheme was successfully tested on a polarization division multiplexing (PDM)-QPSK system at a rate of 112 Gbps. The results indicate that authorized users can correctly decrypt the encrypted information, while unauthorized users can only obtain useful information with a bit error rate (BER) of approximately 0.5, verifying the effectiveness and security of the encryption scheme.
We proposed and numerically studied a traceless encryption approach for physical layer security in coherent optical communications system, the most attractive advantage of which is that it is hard for eavesdroppers to be aware that the transmission signal has been encrypted because the modulation formats of encrypted signal are still the regular ones, i.e. traceless encryption. In the proposed approach, the phase only or the combination of phase and amplitude dimensions can be used for encryption and decryption. Three simple encryption rules are designed and used to investigate the encryption security performance of the scheme, in which the QPSK signal can be encrypted to be as 8PSK, QPSK and 8QAM. The results show that three simple encryption rules can cause 37.5%, 25%, 62.5% of user signal binary codes to be misinterpreted by the eavesdroppers, respectively. When the modulation formats of encrypted signal and user signal are identical, the scheme can not only cover up the real information, but also have a potential application at misleading eavesdroppers. The impacts of the control light peak power at the receiver on the decryption performance are also analysed, the results indicate that the decryption performance of the scheme has a good tolerance to the peak power fluctuation of control light at the receiver.
Abstract This paper presents a novel multi-layer secure communication system that bases 2D-OCDMA technology to enhance the security and number of users of the system. The system innovatively combines RSA encryption, polarization multiplexing, and address coding techniques to protect and transmit the data. At the transmitting end, the data is encrypted by algorithm and then encoded by address code. The encoded optical data is split into two orthogonal polarization states and sent over the same channel. At the receiving end, only the optical signals in the matching polarization state can be retrieved by the polarizer with the right angle. The retrieved data is then decoded by the address code and decrypted by the algorithm to recover the original data. This system achieves multi-layer security and capacity enhancement by processing the information at different layers. The feasibility of the system is demonstrated by joint experimental simulation using Java programming language and Optisystem simulation software. In this paper, low BER transmission of 4 code words for 8 users 50 km 1Gbit/s is realized using optical orthogonal codes (OOC) with BER around 10−30. It realizes the enhancement of 4-user to 8-user without affecting the transmission effect.
The optical network supporting emerging bandwidth-intensive services has become the cornerstone of the 5G era. However, the development of optical fiber eavesdropping and quantum computing has brought huge security challenges to traditional cryptography. As an effective approach to improving optical layer transmission security, all-optical logic gate encryption has important research significance. This paper proposes a high-speed coherent optical encryption and decryption system based on phase encoding with all-optical logic gates. The system ingeniously designs the phase encoding and decoding scheme between two quadrature phase-shift keying (QPSK) signals, which doubles the encryption and decryption efficiency. In addition, the integration of physical-layer key distribution (PLKD) and physical-layer encryption (PLE) contributes to a reduction in overall system complexity. By adopting real-time signal processing in an all-optical domain, the single-wavelength rate of system security communication can reach 100 Gbps. The system is also applicable to other phase-modulated signals and provides a feasible scheme to enhance transmission security in wavelength division multiplexing (WDM) optical networks featuring high speed, low latency, and high flexibility.
A novel digital signal processing (DSP)-based scheme for physical layer security in coherent optical communication systems is proposed and numerically investigated. The optical layer signal encryption is accomplished by two dispersive elements and one phase modulator (PM) driven by a DSP-generated encryption key, whilst signal decryption uses similar components but with inverted dispersion values and security keys. A critical aspect of the DSP-based physical layer security is that the security keys, driving the PMs to hide/recover the data signals, must be highly unpredictable and noise-like, thus orthogonal frequency division multiplexing (OFDM) signals are employed as they possess these characteristics, they can also be easily generated and cover a suitably wide range of unique keys. Numerical simulations are conducted to determine optimum system parameters for achieving a high level of security, the key parameters requiring optimization are the dispersion of the dispersive elements and the bandwidth of the security keys. Using these determined optimum parameters, in-depth investigations are undertaken of encryption/decryption induced transmission performance penalties, sensitives to various parameter offsets and operation over various transmission distances. To observe any data signal dependencies, various performance metrics are investigated for different combinations of modulation formats (DQPSK and 16QAM) and baud rates (40 Gbaud and 100 Gbaud) for the transmitted data signals. The proposed DSP-based physical layer security scheme is shown to have the potential to achieve, in a low-cost and highly effective manner, a high level of physical layer security with acceptable performance penalties for existing coherent optical communication systems.