Fawk PDF Tools is a 100% client-side web application (pdf.js + pdf-lib). Documents opened in Fawk PDF Tools are processed entirely inside your local browser memory and are never uploaded to any remote server or third-party service (unless you configure your own optional Nextcloud WebDAV proxy).

Redaction in Fawk PDF Tools operates by raster-flattening redacted pages (raster_flatten method). When redacting a page, the page layout and underlying text/vector streams are replaced with a high-resolution flattened raster JPEG image stream. This guarantees that text under black boxes cannot be searched, selected, or extracted from the exported PDF stream.

If you discover a potential security vulnerability or stream privacy defect in Fawk PDF Tools, please report it privately via GitHub Security Advisories or contact the maintainer directly. Please do not open public issues for unpatched security vulnerabilities.