Pre-Processing-Based Walsh Code With Switched System in Secure Image Steganography Enhancement

This paper proposes a pre-processing encryption then hiding scheme that enhances image security in steganography. The method combines a Walsh code with switched linear system encryption, followed by Discrete Wavelet Transform and Singular Value Decomposition (DWT-SVD) for secure image hiding. The Walsh code is considered as the switching signal of the switched linear system, which offers benefits in image encryption due to its characteristics of left invertibility and flatness. Additionally, with the aid of the Walsh code generator, the key matrix will be formed to enhance the image encryption security. To hide the encrypted secret image in another image, the DWT-SVD method will be applied to obtain the frequency-domain representation, which is then transformed into the singular values of the secret image. Consequently, the matrix manipulations between SVD matrices of both the encrypted secret image and cover image complete the embedding process of steganography. The contribution of this scheme lies in its simplicity of hardware use while achieving high security. Finally, the simulations are shown to demonstrate the effectiveness of this scheme. The metrics such as Mean Squared Error (MSE), Peak Signal-to-Noise Ratio (PSNR), Bit Correction Ratio (BCR), and Structural Similarity Index Measurement (SSIM) are examined to evaluate the security level of the proposed scheme.