An efficient data hiding for ECG signals based on the integer wavelet transform and block standard deviation

Herein, we present an improved electrocardiogram (ECG) steganography for the protection of patients’ sensitive data, such as blood pressure, glucose level, lipid profile, and other personal health information. Based on the integer wavelet transform (IWT), we concealed secret bits in an ECG host using the standard deviation (SD) block, coefficient alignment technique, and least significant bit replacement. By computing the SD of a host block before bit embedding, data bits can be effectively embedded in the IWT coefficients. Simulations revealed that the payload of the proposed method is superior to that of existing techniques when the payload size is larger than 15.5 Kb, and our signal-to-noise ratio (SNR) is also better than theirs. In addition, our method is superior to other ECG steganographic methods in terms of the peak SNR and hiding capability. The proposed method not only provides good perceived quality but also protection against attacks. With its short implementation time, our proposed method can be applied in portable biometric devices or wearable electronics.