Replacing IDs by Psuedonyms does not really give anonymity. Consider correlation with CCTV cameras, or identification based on sleeping in a house. As an hypot

Replacing IDs by Psuedonyms does not really give anonymity. Consider correlation with CCTV cameras, or identification based on sleeping in a house. As an hypothetical, suppose there is data on two people, who were in the same house at 11:00 pm. Then, at 12:00 pm, one of those people moved over to a neighboring house for 1:00 hour, after which they went back. It looks a lot like two people who live together, where someone snuck out to spend the night with someone else. This is sensitive data, and not really anonymous.