A Systematic Survey, Classification and Analysis of Stegano-Encryption Techniques for Medical Images

Right information at the right time and only to the right recipient is a pivotal requirement of modern-day communication systems. Classified information, being an important asset, must be protected against snooping, alteration and, fabrication. This is even more important for personally identifiable medical records, owing to the sensitive and private nature of patients information. Secure storage and exchange of medical information are often challenged by evolving threat landscape, which is consistently being nurtured by sophisticated attack-vectors, ever-rising count of security vulnerabilities and un-educated and un-aware users handling this critical information. Traditional approaches of cryptography and steganography are normally deployed to protect/hide medical records; however, they often suffer from implementation flaws. Steganography can shield the data by hiding it in a cover object but once the presence and encoding scheme of data is revealed, it no longer remains secure. Thus, steganography alone cannot guarantee data privacy and is preferably used in conjunction with an appropriate encryption technique. This research surveys and critically analyzes the security techniques deployed for privacy protection of medical images, in particular, those using a combination of steganography and encryption techniques. The paper scrutinizes the effectiveness, coverage and implementation viability of some of the recent techniques over medical records and discusses their strengths and weaknesses in a systematic fashion. The survey follows a thematic approach to classify available approaches with regards to different methods used and is further grouped in chronological order to develop insight regarding the research contributions made in this field over the time scale. These classifications are further used to identify research gaps and pinpoint future research directions.