Robust Secret Image Exchange Resistant to JPEG Compression

For real-world Secret Information Sharing (SIS) applications, robust secret image sharing (ROSIS) which is developed for JPEG images and resistant to recompression is required because of the prevalence and regularity of JPEG recompression. The error-correcting codes (ECC)-based state-of-the-art ROSIS now in use is limited to JPEG compression having quality factors (QFs) around 99 and 100. Nevertheless, it produces shadow pictures that are limited within the spatial domain and resemble noise. The robustness of the scheme is significantly increased by using a stable block condition to ensure the constant existence of discrete cosine transform (DCT) coefficients during JPEG recompression. This novel ROSIS scheme, called SBCROSIS (Robust Secret Image Sharing Scheme Resistant to JPEG Recompression Based on Stable Block Condition), is presented in this paper. We create DCT blocks which either directly or by means of strategic global control comply to stable block conditions by using a secret sharing (SS) mechanism. We also take into account the degree to which the generated DCT blocks and the original cover DCT blocks are comparable. In addition, we developed a customized assessment process especially for ROSIS. Comprehensive test results show that SBC-ROSIS can process JPEG images efficiently, exhibiting strong performance in realistic recompression scenarios and striking a balance between privacy, reliability, hiding, and compliance to the (m, n) threshold without the need for data hiding, ECC, or pixel expansion.