Note that there's a big difference between de-identifying and fully anonymizing data. In general, it's extremely hard to fully anonymize a dataset. De-identif

Note that there's a big difference between de-identifying and fully anonymizing data. In general, it's extremely hard to fully anonymize a dataset. De-identification gets you most of the way there, but its frequently possible for a dedicated attacker to re-identify users by combining the data with public datasets. For example, patient ID e76f57b may be a 38 year old woman in Smalltown. Her medical record states that she gave birth on 3-20-2017. Find all public birth announcements from that day in that town with a 38 year old mother. Once you have a small set of candidates, it's not hard to narrow down farther.