High-security key accompaniment transmission scheme based on constellation flat coding over seven-core fiber.

Area of Science:

• Optical Communications
• Information Security
• Signal Processing

Background:

• Secure data transmission is critical in modern communication systems.
• Existing encryption methods can be vulnerable to sophisticated attacks.
• Physical-layer security offers inherent protection by leveraging unique channel characteristics.

Purpose of the Study:

• To propose a novel seven-core fiber key synchronization transmission scheme.
• To enhance system security by embedding encryption directly into the modulation process.
• To achieve inherent physical-layer security against brute-force attacks.

Main Methods:

• Utilizing constellation flat coding (CFC) to map binary keys to silent subcarriers.
• Employing a four-dimensional (4D) chaotic model for data encryption (XOR, CFC rules, masking).
• Implementing 3D constellation mapping, flattening to 2D, and dimension masking for chaotic encryption.

Main Results:

• Experimental validation on a 56 Gb/s 3D index modulation (IM) CFC signal over a 2 km seven-core fiber.
• Minimal signal difference (<0.1 dB) observed across fiber cores.
• Achieved a bit error rate (BER) of approximately 0.5 for 2D-CFC demodulation with key mismatch.

Conclusions:

• The proposed scheme effectively couples index selection, constellation mapping, and chaotic modulation for inherent security.
• The vast chaotic seed parameter space (~10^109) renders brute-force attacks infeasible.
• This approach provides a robust physical-layer security solution for optical communication systems.