Medical image watermarking using RSA encryption in wavelet domain

Abstract

This research highlights the use of encryption based medical image watermarking of three types of medical images namely, MRI, CT and Ultrasound. The watermark used in this application is patient image. The watermark patient image is encrypted using a public Key encryption with RSA algorithm. Cover image is a medical image of standard resolution to be watermarked. The RSA encrypted patient image is embedded into the medical cover image in wavelet transform domain. Inverse wavelet transform is applied to produce a watermarked medical image with patient image as watermark. The watermarked image is tested in both visual quality and quantitatively using psnr and normalized cross correlation(ncc). The extraction processing is done with the help of Private Key in wavelet domain. The algorithm was tested for all three types of medical images and using db2 mother wavelet for level-2 decomposition. Attacks are planned on the extraction process and encrypted watermark is extracted successfully.