Anonymize or pseudonymize: what is the difference?

October 30, 2026 · Zecretly

In short: Anonymizing makes a person impossible to identify, and the step is final. Pseudonymizing replaces details with placeholders, and a separately kept mapping allows you to put them back. Zecretly works reversibly, which makes it technically a tool for pseudonymizing.

What does anonymizing mean?

Anonymizing removes the link to a person so that the person can no longer be identified. There is no way back. Data that is truly anonymous generally no longer counts as personal data. That is hard to achieve, though: often a few details taken together are enough to show who is meant.

What does pseudonymizing mean?

Pseudonymizing replaces details such as names with placeholders, for example [PERSON_1]. The mapping between placeholders and real values is kept separately. Whoever holds it can identify the person again. The GDPR describes this in Article 4(5): the data can no longer be attributed to a person without additional information, and that information is kept separately and protected.

Where does Zecretly stand?

Zecretly puts the real values back when you restore. The mapping is stored encrypted (AES-256-GCM) in the folder %USERPROFILE%\.zecretly on your computer. Technically, that is pseudonymizing. In everyday language we say “anonymize”, because the file you share no longer contains the real details.

What follows for you?

• Do not pass on the mapping, that is the folder %USERPROFILE%\.zecretly.
• Delete case files in the settings when you no longer need them. After 30 days without use, Zecretly deletes them the next time it starts.
• How your case is classified legally is for you and your legal counsel to decide, not Zecretly.