Hybrid chaotic substitution and block-DCT-based ECG steganography with boosted embedding capacity
Neetika Soni, Indu Saini, Butta Singh · Research on Biomedical Engineering · 2021
A novel idea of exploiting the chaotic sequences for substitution in the DCT coefficients of ECG signal according to the secret data is proposed in this work. The chaotic values are selected as per the decimal number generated from a bundle of secret bits. The selected chaotic values sensibly manipulates only the low- energy DCT coefficients, thus preservinge the diagnostic features of the ECG signal. The approach engenders unprecedented rise in the eEmbedding cCapacity (EC) as every substitution involves secret bits equal to the bundle size. The remarkable feature of the approach is that unlike existing steganography techniques, the perceptual quality of the stego-ECG is minimally affected with increase in the EC. The performance of the proposed technique is evaluated in terms of non-diagnostic distortion measures and clinically diagnostic error measures, while EC and bit error rate (BER) assess the steganography efficiency. The security analysis done in terms of key space verifies the robustness of the algorithm. The experimentation is done on the standard databases (both normal and abnormal) as well as on the self-recorded database. An average PRD, PSNR, WWPRD, WEDD and EC measured on all 48 records of MIT-BIH arrhythmia database of 5 min come out to be 2.51 × 10 −3 , 55.82, 0.088, 4.45 × 10 −3 and 4.16, respectively marking the competency of the proposed technique in ECG steganography applications.