Physical layer encryption scheme based on cellular automata and DNA encoding by hyper-chaos in a CO-OFDM system

Area of Science:

• Optical Communications
• Cryptography
• Information Security

Background:

• Coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems are vulnerable to security threats.
• Existing encryption methods may lack sufficient randomness and complexity for robust security.

Purpose of the Study:

• To propose and evaluate a novel encryption scheme for CO-OFDM systems.
• To enhance data security and confidentiality in optical communication networks.

Main Methods:

• Combining cellular automata (CA) for pseudo-random binary sequence (PRBS) generation with complex DNA encoding.
• Utilizing a 4-dimensional hyper-chaotic system for generating unpredictable key sequences.
• Implementing a 6-variable key system with a key space of approximately 10^138.

Main Results:

• The proposed encryption scheme significantly improves scrambling effect and randomness compared to conventional DNA encoding.
• Experimental results in a 40 GHz 16QAM CO-OFDM system over 80 km SSMF demonstrate successful decryption by authorized users.
• Eavesdroppers could not derive useful information, with a bit error rate (BER) around 0.5.

Conclusions:

• The integrated CA and DNA encoding approach offers enhanced security, randomness, and complexity for CO-OFDM systems.
• The encryption scheme provides effective protection against unauthorized access.
• A minor OSNR penalty of 0.5 dB is observed due to CA error propagation, which is acceptable for the achieved security level.