Optical robust zero-watermarking scheme based on chaotic facial phase masks and diffractive imaging

Area of Science:

• Optics and Photonics
• Digital Image Processing
• Cryptography

Background:

• Traditional optical watermarking faces trade-offs between imperceptibility and robustness.
• Existing schemes lack user-identity-linked encryption, creating security vulnerabilities.

Purpose of the Study:

• To propose a secure and robust optical zero-watermarking scheme.
• To overcome limitations of embedding-based watermarking and key management.

Main Methods:

• Encoding watermarks into noise-like images using chaotic facial phase masks and diffractive imaging.
• Generating zero-watermarks by XORing encoded watermarks with host image texture features (variational image decomposition).
• Recovering watermarks using host image features, iterative phase retrieval, and user's facial image.

Main Results:

• The proposed scheme achieves high security by using biometric facial features as encryption keys.
• Demonstrated strong robustness against various image processing operations and geometric attacks.
• Achieved approximate lossless recovery of the original watermark.

Conclusions:

• The novel optical zero-watermarking scheme offers enhanced security and robustness.
• Biometric-based keying eliminates storage and transmission risks.
• The method is effective for secure digital image protection.