Encryption + Watermarking: A Duo Approach for Secure Image Communication in Transform Domain

When images are transmitted over networks, there is a risk of interception by malicious users. Encrypting images before transmission ensure that even if intercepted, the images remain unreadable without the decryption key. Integration of image encryption and watermarking involves combining techniques to protect the confidentiality and authenticity of digital images. This paper proposes the combination of image encryption and watermarking; firstly, the Rubik’s cube approach is used to scramble the secret image, followed by diffusion, which is implemented using Fourier random phase encoding. Concurrent to the image encryption scheme, wavelet sub-band coding is applied for the cover image, which results in frequency sub-bands, and then the encrypted image is embedded on the LL band of the cover image, and embedding is progressed with random location selection with the reference of kuberakolam as a randomization index. The novelty of the proposed work is that diffusion is implemented in the frequency domain with Fourier random phase encoding and embedding using random location selection with the reference of kuberakolam and well in the LL sub-band of the wavelet transform. The proposed work is done in hybrid mode spatial and transform domain, and this integration is particularly important in scenarios where sensitive or valuable images need to be securely transmitted and shared. The proposed encryption work is validated and proved using statistical attack and differential attack, and the watermarking progress is validated using imperceptibility and robustness.