It is the technology that led to the massive generation, proliferation, and sharing of data that changed even the human behavior. While it has immensely benefited many useful tools and techniques, it is obviously a double-edged sword. An example is the face recognition from images of public data to spot criminals, missing children, etc., where at the same time it is an invasion of privacy and may even lead to unforeseen criminal activity too. We have to resort to technology itself to find a solution to this dilemma between openness/sharing of data to protection/regulatory regime. Two reasons for this. One, I believe that it is difficult to predict or control human behaviors and motives. Second, any complex encryption of data, taller/thicker firewalls, and deeper hiding of data may not ensure safety as infringement by ingenuous (often miscreant) minds. Human errors and bugs in technology (like the Intel CPU architecture flaw) could be another source of windows of opportunity for misuse and unauthorized access.
While I agree that 100% foolproof data protection may a utopian dream, another approach - may be bit controversial - is to make the data more open, transparent, and trackable. Let the data be embedded with information on its credentials and the tools may look for the credentials and notify the owners before processing. That may be a better answer for so called "undesirable but not necessarily unauthorized access" such as what happened with Cambridge Analytica scenario.
In addition to trying to protect by not allowing to access the data, another way to safeguard is making the data transparent, but tracking the access such as who is downloading, who is using etc. Rather than hiding the data, if we focus on the tools and containers of data to examine whether it is authenticated to process or keep the data.
In short, let us make data more “self-aware”, develop "smart data containers", and make the tools for data processing/analyzing more “socially-sensitive” which would help us track and notify the movements of data. It is a kind of “electronic anklets” or “soft-surveillance” for data by which we are not trying to prevent the movements of data but track and monitor the movements. Not that this would prevent 100% of unauthorized access, however, it could reduce some extent of misuse because of the fear of being tracked, at the least!!!
