Cryptographic and Steganographic Approaches to Ensure Multimedia Information Security and Privacy

Information security and privacy have traditionally been ensured with data encryption techniques. Generic data encryption standards, such as DES, RSA, AES, are not very efficient in the encryption of multimedia contents due to the large volume. In order to address this issue, different image/video encryption methodologies have been developed. These methodologies encrypt only the key parameters of image/video data instead of encrypting it as a bitstream. Joint compression-encryption is a very promising direction for image/video encryption. Nowadays, researchers start to utilize information hiding techniques to enhance the security level of data encryption methodologies. Information hiding conceals not only the content of the secret message, but also its very existence. In terms of the amount of data to be embedded, information hiding methodologies can be classified into low bitrate and high bitrate algorithms. In terms of the domain for embedding, they can be classified into spatial domain and transform domain algorithms. Different categories of information hiding methodologies, as well as data embedding and watermarking strategies for digital video contents, will be reviewed. A joint cryptograph-steganography methodology, which combines both encryption and information hiding techniques to ensure patient information security and privacy in medical images, is also presented.