Rademacher-Based Pixel and Color-Channel Selection for Robust Image Steganography

Abstract

This paper proposes a novel image steganographic method based on discrete Rademacher functions combined with Least Significant Bit (LSB) embedding. Unlike conventional sequential LSB techniques, which modify pixel values in a deterministic scan order, the proposed approach introduces a mathematically structured selection mechanism that governs both spatial embedding locations and, in the case of color images, channel selection. The performance of the proposed method is evaluated using standard benchmark images, including grayscale and color versions of the Lena, Tank, and Pepper datasets at a resolution of 512 × 512 pixels. The quality of stego-images is measured using Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM), ensuring both pixel-level accuracy and perceptual similarity assessment. Experimental results demonstrate that the proposed method maintains PSNR values above conventional acceptability thresholds and SSIM values close to unity across various embedding rates. Comparative analysis with classical sequential LSB embedding confirms that the proposed approach achieves comparable or improved imperceptibility, particularly in color images due to distributed channel embedding. The results indicate that Rademacher-based LSB steganography offers a favorable trade-off between embedding capacity, visual quality, and security.