Mode division multiplexing chaotic encryption scheme based on key intertwining and accompanying transmission

Area of Science:

• Optical Communications
• Physical Layer Security
• Information Encryption

Background:

• Mode Division Multiplexing (MDM) enables higher data rates by utilizing multiple spatial modes in optical fibers.
• Existing chaotic encryption schemes face challenges in key management and security against advanced attacks.
• Few-mode fibers (FMF) offer a platform for MDM but require robust security protocols.

Purpose of the Study:

• To propose and experimentally demonstrate a novel MDM chaotic encryption scheme.
• To enhance physical layer security through key intertwining and accompanying transmission.
• To evaluate the security and performance of the proposed encryption scheme.

Main Methods:

• Utilizing a weakly coupled few-mode fiber (FMF) for simultaneous data and key transmission in LP01 and LP11 modes.
• Implementing a time-varying key generation by XORing current and preceding keys.
• Applying chaotic masking in the digital domain at constellation, symbol block, and subcarrier levels.

Main Results:

• Successful transmission of an 8.89 Gb/s encrypted 16QAM-OFDM signal over 1 km of FMF.
• Normal data recovery with the correct key and a Bit Error Rate (BER) around 0.5 for illegal receivers.
• A cracking efficiency threshold 5.21 × 10^6 times higher for the time-varying key compared to time-invariant keys.

Conclusions:

• The proposed MDM chaotic encryption scheme offers robust physical layer security.
• Key intertwining and accompanying transmission in FMF provide enhanced data protection.
• This approach is a promising candidate for secure optical communication systems.