Re-Identification is about: What is re-identification? When user data is processed at a company, special algorithms decouple sensitive information like location traces and medical records from identifying details like email addresses and passport numbers. This is called de-identification. It may be reversed, so organizations can recover the link between the users’ identities and their data when needed. Such controlled re-identification by legitimate parties happens routinely and is perfectly appropriate, so long as the technical design is safe and sound.