Medical image watermarking for secure e-healthcare applications

In telemedicine, medical data are exchanged between hospitals and healthcare professionals to facilitate patient care. This transmission will expose the medical data to several security threats and most existing security mechanisms such as cryptographic techniques secure data from unauthorized access but this protection is only valid when the data are encrypted. In order to overcome these limitations, we propose in this paper a watermarking approach for patient identification and watermark integrity verification. In this approach, the watermark consists of two parts, the first part contains the patient’s information fingerprint, and the second part contains the patient’s encrypted photography. For the integration process, a discrete wavelet transform is applied to divide the medical image into four sub-bands. The watermark bits are then integrated by modulating the obtained mid-frequency coefficients. This approach’s capacity allows the integration of the patient’s photography and fingerprint, but will also be sufficient for a possible error-correcting code addition. The coefficient modulation performed by the integration process allowed hiding the watermark in an imperceptible way. From the experiments results, we can conclude the use of discrete wavelet transform allows generating a watermarked image almost similar to the host signal. The robustness results also confirm the watermark resistance to various attacks commonly used in watermarking.