Reversible ECG Watermarking for Ownership Detection, Tamper Localization, and Recovery

Security is unarguably the most important aspect when it comes to transmission and handling of medical data. Technological development has done wonders in the analysis of medical images as well as physiological signals. On the other hand, it posed a serious question of security threat for these signals. Schemes like cryptography, steganography, and watermarking are employed to ensure medical signal safety. All schemes have their strengths and flaws. Encryption provides a strong answer toward data security but it cannot withstand signal tampering. On the other hand, steganography is a creative method for data security but it introduces permanent changes in the signal. In proposed work, a reversible watermarking scheme has been developed for electrocardiogram (ECG) signal security. To the best knowledge of authors, proposed method is the first of its kind, i.e., capable of ownership establishment, tampering detection, and recovery of ECG signal (in case of tampering). It uses prediction error expansion (PEE) for reversible watermarking. The proposed algorithm is capable of maintaining 100% reversibility when no tampering is performed on the watermarked signal. In case of tampering, the proposed algorithm is capable of partially restoring tampered ECG signal highlighting prominent parts.