Professor A's interests: "Cloud Security, the Internet of Things, Digital Forensics, Mobile Malware Security, Secure Provenance, Biomedical Device Security, Social Network Security, Database Security"
Professor B's interests: "Medical Image Analysis, Medical Robotics, Digital Image Processing, Algorithms and Data Structure, Computer Organization"

So.., how do I pick a topic? I must admit my mind is very flat: I'm better at following instructions than being original. I think hardware is interesting indeed, but,.. what do I do to find out what to research?
(I have to do research, opting out is not much of an option compared to the others)