Hiding Encrypted Messages in Medical Images using Dwt Technique

Today, with the invent of modern technological applications, it requires a greater security measure to transmit confidential data over various unsecure networks particularly in the fields of military, medical Infrastructure and so on. It can be sent through various communication channels that includes multimedia media like audio/video, electronic signals etc. To transmit information securely, different methods like steganography or cryptography can be used. The term steganography has its derivative from the Greek words “steganos” meaning hidden or covert and graphia meaning writing.Steganography can be defined as a way of hiding a confidential file, text information, or any other multimedia content (image, video or audio)into any other multimedia carrier file. In this work, steganography based on Discrete Wavelet Transform (DWT) method is proposed where in the secret data is inserted in the modified coefficients of the cover image. The proposed steganography method is implemented in the frequency domain. This approach caters to the needs of users based on the capacity and quality of inclusion data to be transmitted using medical images. To attain this, the recommended algorithm comprises of converting the message into encrypted text using the modified AES algorithm with 8x8 state matrix and incorporating information of encrypted text into medical images. Contrasting to the spatial domain methods, the encrypted confidential messages will be are assimilated into the high frequency coefficients which are obtained by applying discrete Wavelet transformation. Experimental results reveal that embedding encrypted data using DWT technique gives good PSNR values to attain high quality stego images.