Encryption of ECG signals for telemedicine applications

Multimedia security has been extensively used in content protection, image authentication, data hiding and signal encryption. Similarly, transmission of biomedical data or information remotely for healthcare applications should be secure. One of the important medical signals that need to be transmitted to healthcare centers is the Electrocardiogram (ECG) signal. This paper is concerned mainly with ECG signal encryption for security applications. The paper presents three cryptosystems for ECG signal encryption based on the fusion of ECG signals with other masking signals that are rich in activities such as speech signals. The common thread between these cryptosystems is the operation on sample values of the ECG signal rather than adopting encoding and decoding schemes, and this saves much time and is more immune to both noise and hacking scenarios. The proposed cryptosystems are compared to the encryption technique that uses 1-D logistic map. The performances of the proposed cryptosystems are evaluated through simulation experiments in terms of histogram, structural similarity index, Signal-to-Noise Ratio (SNR), log-likelihood ratio, spectral distortion and correlation coefficient. It is clear from the experiments that the utilization of more levels of encryption increases the security.