An integer wavelet transform and pixel value differencing based feature specific hybrid technique for 2D ECG steganography with high payload capacity

Abstract

Electrocardiogram (ECG) is essentially a significant physiological signal required in the diagnosis of cardiac disorders. For remote healthcare assistance, ECG signal along with patient’s meta-data is communicated over the public network. During communication, security and privacy of patient’s sensitive information is a major issue. Presently, a common steganography technique is being applied on the entire ECG signal. Since ECG signal consists of clinically more significant QRS regions as well as less significant non-QRS regions and employing same steganography approach on both the regions is not admissible. In this work, a hybrid approach is proposed for concealing the sensitive information in 2-dimensional (2D) ECG. A fusion of integer wavelet transform and modified least significant bit (IWT-mLSB) approach is applied in the pivotal QRS complex region; while pixel inverted pixel value differencing (PI-PVD) technique is implemented in the non-QRS region to hide the confidential data. The performance of the proposed algorithm is evaluated on standard as well as self-recorded database in terms of statistical parameters, clinically critical metrics, heart rate variability (HRV) analysis, embedding capacity (EC) and bit error rate (BER). The security of the proposed algorithm is further evaluated in terms of key space and key sensitivity. A comparative analysis with other state-of-the-art techniques exhibits the competency of the proposed technique.