Securing Medical Data by Combining Encryption and Robust Blind Medical Image Watermarking Based on Zaslavsky Chaotic Map and DCT Coefficients

The transmission of patient records through communication networks requires techniques which guarantee the security and confidentiality of telemedicine means. This paper presents an improved robust blind medical image watermarking algorithm based on two dimensional discrete cosine transform (2D-DCT) and Zaslavsky chaotic map able to increase the size of the embedded watermark and to provide protection of patient data. In the proposed scheme, we use the X-ray, scanner, magnetic resonance, and ultrasound image, the size of gray medical images is 512 × 512 pixels, and the digital watermark is composed from 4096 bits of electronic patient records (EPR) and 4096 bits of binary logo image, so a payload of 8192 bits. The encrypted watermark is embedded in the shuffled blocks of discrete cosine transform coefficients of the medical image using a 256-bit secret key to increase the security. The experimental results show the robustness of the proposed method to various common attacks, for example, JPEG compression, Gaussian noise, salt and pepper noise, filtering, cropping, rotation and histogram equalization. Also, the security analysis, demonstrates that the proposed watermarking algorithm achieves high security.