Double Image Encryption System Using a Nonlinear Joint Transform Correlator in the Fourier Domain.

Area of Science:

• Optics
• Information Security
• Image Processing

Background:

• Traditional image encryption methods face challenges in security and efficiency.
• Simultaneous encryption of multiple images requires robust architectures.
• Double Random Phase Encoding (DRPE) is a known technique but can be improved.

Purpose of the Study:

• To propose a new nonlinear joint transform correlator (JTC) architecture for simultaneous encryption and decryption of two images.
• To enhance security and image quality in optical encryption systems.
• To develop a system with a larger key space for improved security.

Main Methods:

• Implementation of a nonlinear JTC in the Fourier domain (FD).
• Utilizing Double Random Phase Encoding (DRPE) with four Random Phase Masks (RPMs).
• Applying specific nonlinear operations on the Joint Power Spectrum (JPS) to generate a single real-valued encrypted signal.

Main Results:

• Achieved simultaneous encryption and decryption of two images with high quality.
• Generated a single real-valued encrypted signal, increasing security.
• Demonstrated a larger key space due to the use of four RPMs.

Conclusions:

• The proposed nonlinear JTC architecture offers a secure and efficient method for double image encryption.
• The system provides enhanced security against various attacks, including brute force and deep learning.
• Computational simulations validate the feasibility and performance of the proposed system.