Also known as: de-identification · pseudonymization · re-identification
Anonymisation is the process of altering data so that individuals can no longer be identified from it, either directly or by combining it with other available information — as distinct from pseudonymisation, which only replaces identifiers with reversible tokens.
True anonymisation is much harder than removing names. Repeated research has demonstrated that combinations of seemingly innocuous attributes — postcode, date of birth, and sex, or a handful of location points — uniquely identify most individuals in a population.
The legal distinction matters: genuinely anonymised data typically falls outside data protection law, while pseudonymised data remains personal data because re-identification is possible. Organisations frequently claim the former while implementing the latter.
Differential Privacy
Differential privacy is a mathematical framework that adds carefully calibrated statistical noise to data or query results, providing a provable guarantee that the presence or absence of any single individual has negligible effect on the output.
Data Minimization
Data minimisation is the principle that an organisation should collect and retain only the personal data actually necessary for a stated purpose, and no more, for no longer than needed.
GDPR
The GDPR (General Data Protection Regulation) is the European Union's data protection law, which governs how personal data of people in the EU may be collected and processed, and grants individuals rights over their data regardless of where the processing organisation is based.
Metadata
Metadata is the information surrounding a communication rather than its content — who contacted whom, when, for how long, from where, and how frequently — which remains visible even when the content itself is encrypted.
Browser Fingerprinting
Browser fingerprinting is a tracking technique that identifies a user by combining observable characteristics of their device and browser — screen resolution, installed fonts, graphics rendering behaviour, time zone — into a signature distinctive enough to recognise across sites.