Chaotic index modulation and subcarrier intra-block-inter-block shuffling for secure CO-OFDM-PON based on a hybrid 4D chaos

Area of Science:

• Optical Communications
• Network Security
• Cryptography

Background:

• Passive Optical Networks (PONs) are crucial for broadband access.
• Ensuring physical layer security in high-speed optical networks like CO-OFDM-PON is challenging.
• Existing encryption methods may not offer sufficient protection against sophisticated attacks.

Purpose of the Study:

• To propose a novel four-dimensional (4-D) encryption scheme for CO-OFDM-PON.
• To enhance the physical layer security of CO-OFDM-PON systems.
• To achieve ultra-high security encryption through chaotic index modulation and symbol shuffling.

Main Methods:

• A hybrid 4-D chaotic system combining 1-D Cubic and 3-D T-S Fuzzy chaotic mappings generates scrambling factors.
• Index bit encryption uses chaotic many-to-many mapping between index bits and subcarrier activation patterns (SAPs).
• Data bit encryption is achieved via heterodyning with chaotic bits, followed by intra- and inter-block symbol shuffling.

Main Results:

• Simulations demonstrate successful decryption by legitimate users and a near 0.5 Bit Error Rate (BER) for eavesdroppers.
• The encryption scheme supports a 63.76 Gb/s encrypted 16-QAM OFDM-IM signal over 25 km and 80 km SSMF.
• Achieved a key space of 10^210 and 100% scrambling degree (SD), validating ultra-high security.

Conclusions:

• The proposed 4-D encryption scheme effectively enhances physical layer security in CO-OFDM-PON.
• The scheme provides robust protection against eavesdropping, ensuring data confidentiality.
• It is suitable for secure communication applications requiring high-level encryption.