Impulse attack-free four random phase mask encryption based on a 4-f optical system.

Area of Science:

• Optics
• Information Security
• Cryptography

Background:

• Double Random Phase Encryption (DRPE) is a widely used optical encryption technique.
• DRPE is vulnerable to impulse function attacks targeting the Fourier plane Random Phase Mask (RPM).
• The vulnerability arises because the Fourier transform of a delta function is a unity function, simplifying key recovery.

Purpose of the Study:

• To propose a modified 4-f optical setup to enhance the security of DRPE.
• To protect the DRPE system from impulse function attacks by preventing the formation of a unity function in the Fourier domain.
• To validate the proposed scheme's resistance against brute-force and impulse function attacks.

Main Methods:

• Implementing a modified 4-f optical system with Random Phase Masks (RPMs) positioned before both lenses.
• Conducting numerical simulations to analyze the system's performance and security.
• Testing the system's robustness against brute-force and impulse function attacks.

Main Results:

• The modified scheme successfully prevents the formation of a unity function in the Fourier plane.
• Numerical simulations demonstrated the scheme's resistance to impulse function attacks.
• Experimental validation confirmed the feasibility and enhanced security of the proposed optical encryption method.

Conclusions:

• Placing RPMs before both lenses in a 4-f setup effectively secures DRPE against impulse function attacks.
• The proposed method offers a viable solution for enhancing the security of optical encryption systems.
• This approach strengthens the resilience of DRPE against known cryptanalytic attacks.