Secure communications using nonlinear silicon photonic keys.

Area of Science:

• Photonics
• Quantum Information Science
• Integrated Optics

Background:

• Traditional secure communication relies on large, electronically stored cryptographic keys.
• Physical unclonable functions (PUFs) offer a hardware-based security approach by leveraging unique physical properties.
• Integrated silicon photonics provides a scalable platform for advanced optical functionalities.

Purpose of the Study:

• To develop a novel secure communication system utilizing photonic physical unclonable functions (PUFs).
• To demonstrate the generation and extraction of substantial cryptographic key material from integrated micro-cavity devices.
• To evaluate the performance and security of the proposed system in a practical communication scenario.

Main Methods:

• Construction of a secure communication system using pairs of nonlinear photonic PUFs based on integrated silicon micro-cavities.
• Probing micro-cavities with spectrally-encoded ultrafast optical pulses to elicit chaotic lightwave responses.
• Experimental demonstration of key material extraction and secure communication using the PUF responses.

Main Results:

• Extraction of 2.4 Gb of secure key material from a single micro-cavity PUF device.
• Achievement of bit error rates below 10^-5 at code rates up to 0.1 in secure communication experiments.
• Demonstration of enhanced security by avoiding transmission or digital storage of PUF responses.

Conclusions:

• Integrated silicon micro-cavity photonic PUFs offer a highly secure and compact solution for cryptographic key generation.
• The proposed system is robust, inexpensive, and compatible with existing telecommunications infrastructure.
• This technology is suitable for applications requiring high security, such as one-time pad or public key exchange.