Secure key generation and distribution scheme based on two independent local polarization scramblers

Area of Science:

• Quantum Information Science
• Optical Communication Systems
• Cryptography

Background:

• Secure key exchange is crucial for modern communication security.
• Existing methods face challenges in practical implementation and real-world conditions.
• Optical fiber communication offers potential for secure key distribution.

Purpose of the Study:

• To propose and validate a practical secure key generation and distribution (SKGD) scheme.
• To leverage optical fiber polarization properties for secure key exchange.
• To achieve high bit generation rates and robust security in real-world fiber links.

Main Methods:

• Utilizing two polarization scramblers for active modulation of optical fiber polarization.
• Implementing the scheme in a point-to-point communication system over 20 km of standard single-mode fiber.
• Analyzing signal correlation and bit error rates at a 1 KHz scrambling rate.

Main Results:

• Demonstrated high signal correlation between legal users.
• Achieved a bit generation rate of 1216 bit/s.
• Reported a low bit error rate of approximately 0.33%.

Conclusions:

• The proposed SKGD scheme is practical for real-world applications.
• The method offers high security due to key signal invisibility and difficult recovery.
• The system effectively utilizes optical fiber polarization for secure and efficient key distribution.