Traceless encryption approach for physical layer security in coherent optical communications system

Area of Science:

• Optical Communications
• Physical Layer Security
• Cryptography

Background:

• Coherent optical communication systems are vulnerable to eavesdropping.
• Existing encryption methods can alter signal characteristics, alerting potential intruders.
• There is a need for undetectable encryption techniques in optical networks.

Purpose of the Study:

• To propose and numerically investigate a traceless encryption approach for physical layer security in coherent optical communications.
• To evaluate the security performance and feasibility of the proposed encryption scheme.
• To analyze the impact of decryption parameters on the system's robustness.

Main Methods:

• Numerical simulation of a coherent optical communication system.
• Implementation of a traceless encryption technique using phase and/or amplitude modulation.
• Design and application of three distinct encryption rules.
• Analysis of eavesdropping misinterpretation rates and decryption performance under varying control light power.

Main Results:

• The proposed traceless encryption effectively disguises Quadrature Phase-Shift Keying (QPSK) signals into formats like 8PSK, QPSK, and 8 Quadrature Amplitude Modulation (8QAM).
• Encryption resulted in significant misinterpretation rates for eavesdroppers: 37.5% for 8PSK, 25% for QPSK, and 62.5% for 8QAM.
• When the encrypted signal's modulation format matched the original, the scheme concealed information and could mislead eavesdroppers.
• The decryption performance demonstrated good tolerance to fluctuations in control light peak power at the receiver.

Conclusions:

• The developed traceless encryption method offers a promising solution for enhancing physical layer security in optical communications.
• The scheme's ability to maintain regular modulation formats makes it difficult for eavesdroppers to detect encryption.
• The encryption approach provides flexibility in security levels and robustness against receiver power variations.