Patch-based Reversible Steganography for Secured Communication over Wireless Channels

Securing the perceptual quality of the cover image (CI) and acquiring higher security for hidden information in stego images (STIs) are two sides of the same coin. There is always a trade-off between perceptual quality and level of security when secret bits (SBs) of the secret image (SI) are embedded in a CI. Non-reversible techniques are adopted where a higher level of security is required as in communication, while reversible schemes are preferred to maintain the visual quality of the CI. This article proposes a novel Patch-Based LSB Embedding (LSBE) Data Hiding (PB-LSB-EDH) scheme that provides better security to SBs and maintains stego quality. The scheme embeds a secret byte in a 3x3 patch of the CI. The starting byte in the neighborhood where the SBs are hidden is computed from the center pixels of the 3x3 patch window and continues to embed pixels clockwise. The PB-LSB-DH scheme is highly immune to external noise or attacks when the intensity value of the center pixels is equal to or greater than 12 since the starting index of bit embedding is computed using a natural logarithm. Experimental analysis of four different CIs and SIs showed that the proposed PB-LSB-DH scheme maintains the better perceptual quality of the CI and a higher peak signal-to-noise ratio (PSNR) above 50.