Security enhancement in image steganography for medical integrity verification system

Nowadays image steganography has major role in confidential medical image communication. When the medical image is transmitted through insecure public network, there is a chance for tampering medical images. Therefore, it is crucial to check the integrity of medical images to prevent any unauthorized modification. To check the integrity we calculate cryptographic hash function of ROI (Region Of Interest) by using SHA algorithm. The hash value (H1) will be embedded in the RONI using discrete wavelet transform. By comparing the hash value at receiver side, we can check the integrity of medical image. If any tampering occurs, the hash function does not match. This paper proposes a new method to improve the security. The modified medical image is embedded in an ordinary looking image by spatial reversible steganography method. It helps to conceal the existence of secret medical data. It ensures that the eavesdroppers will not have any suspicion that medical image is hidden in that image. This combined approach will give enhanced security.