Chaos based Medical Image Encryption Techniques: A Comprehensive Review and Analysis

In the past two decades, we have seen the proliferation of Internet and its applications. The information exchange happens via images, videos, texts, audio clips, etc. Medical experts use images as the most common form of information exchange such as X-rays, MRI scans, CT scans, etc. These scanned images contain confidential information about a patient. With images being the most attractive mode for medical information exchange, it becomes the target of many security attacks. Many researchers have put out their best efforts to protect the images from these attacks by proposing several techniques. Despite all efforts, many cryptosystems still compromise with one or more key attributes like efficiency or time required for them to be top-notch. Along with an appreciation of work, careful inspection is also required that can influence the future work and make them better. Hence, this survey aims to summarize and analyze the existing chaos-based medical image encryption techniques introduced in the last five years. The paper starts with a brief introduction about the basic chaos maps, security parameters, and then, progresses to analysis of the encryption algorithms based on categories followed by comparative study and open security issues.