What is Redaction?

Redaction refers to the permanent removal or rendering illegible of confidential information in documents. In the context of PDF documents, redaction means that personal or sensitive data such as names, addresses, IBANs, or phone numbers is irreversibly removed from the document. The redacted sections are replaced with black or colored bars, so that the original text can no longer be reconstructed.

A common misunderstanding is the difference between redaction and covering. If you merely overlay text with a colored rectangle, the underlying text remains in the PDF file and can be revealed again using simple tools. True redaction physically removes the text from the document. Datenmaske uses MuPDF (applyRedactions) to remove the original text from the content stream and replace it with an opaque area — the result is irreversible.

PDF redaction is required in Germany in particular under the GDPR, the IFG (Informationsfreiheitsgesetz, Freedom of Information Act), and for file inspection claims. Public authorities, lawyers, companies, and medical institutions are legally obliged to remove personal data before disclosure.