A Lightweight Dual-Layer Framework for Image Protection Using DWT-DCT Watermarking and Lossless Chained XOR Secret Sharing

Ensuring digital image security over public networks requires both content privacy during transmission and verifiable ownership after recovery. Standard watermarking proves ownership but leaves image content exposed, while secret sharing conceals the visual content but cannot track ownership once shares are merged. To resolve both limitations, this paper presents a practical dual-layer security framework. First, an imperceptible watermark is embedded into the host image using a hybrid Discrete Wavelet Transform (DWT) and Discrete Cosine Transform (DCT) approach. Second, the watermarked image is split into uninformative shares using a lightweight chained Exclusive-OR (XOR) secret sharing scheme. Experimental results demonstrate that the watermarked image maintains high perceptual fidelity with minimal distortion and effectively survives common signal processing attacks. The generated shares exhibit noise-like random properties with zero-pixel expansion, and combining all shares achieves exact lossless reconstruction with zero error in low computational time. Consequently, the framework provides a robust and efficient solution for secure multimedia distribution.