Employment of Enhanced Coefficient Adjustment Technique and Module-based Substitution to Hide Secret Message in ECG Signal

We present an effective electrocardiogram (ECG) steganography technique for concealing patient’s diagnosis and sensitive information within ECG signals. The method utilizes the enhanced coefficient adjustment technique (ECAT) and module-based substitution to embed a large number of secret bits into an ECG host. The proposed method consists of two stages. In stage I, data bits are hidden in a host bundle derived from an ECG with a size of 1 × (n − 1) using ECAT, following two predetermined rules. If the rules are not met, module-based substitution is employed in the bundles. Stage II follows a similar procedure, but with the host bundles enlarged to a size of (1 × n). Simulations demonstrate that the payload and signal-to-noise ratio (SNR) of our method surpass those of existing methods. Additionally, our method ensures good perceived quality and offers protection against attacks. The proposed method finds application in biometric measurements, including portable healthcare devices and IoT-based health monitoring systems.