Wavelet Selection for Novel MD5-Protected DWT-Based Double Watermarking and Image Hiding Algorithm

In today’s interconnected world, massive amounts of data in various forms are transferred across the Internet in a variety of ways for various purposes. Data sharing through a shared communication channel emphasizes the need of data security. Watermarking systems based on discrete wavelet transform (DWT) are widely used for image authentication. Incorporating additional hash code-based security makes it easier for the receiver to detect any tampering with the image. This research study proposes a novel algorithm that combines the advantages of both cryptographic hash function MD5 and DWT. It puts forth a double watermarking scheme, which embeds a visible as well as an invisible watermark on an image and further applies MD5 hash to the watermarked image prior to transmission to generate a hash code which is shared with the receiver, who can recompute the hash code at the end and also verify the visible watermark to easily ensure that the image is received tamper-free. If the receiver attempts to misuse it after removing the visible watermark, then the invisible watermark, known only to the real owner, can still be extracted with an acceptable PSNR from this tampered image. The watermarking scheme proposed can also be applied to hide an image inside another image for the purpose of secret communication between two people. This research study analyzes the use of different types of wavelets for watermarking images by comparing the MSE, PSNR, and SSIM values and finds ‘bior3.1’ as the best-suited wavelet.