PDFの墨消し

This PDF redaction tool permanently removes sensitive text instead of just hiding it behind a black rectangle. You draw boxes over the parts to hide, and each page is flattened to an image with the boxes baked in, so the original words are gone for good.

The obvious approach, drawing a black box in a PDF editor, often fails. The text usually still sits underneath the box in the file's text layer, where anyone can select it, copy it out, or strip the box away. Real redaction has to destroy the underlying content, not cover it.

Each page is rendered to an image with the black boxes burned into the pixels, then rebuilt into a new PDF. There is no text layer left beneath the redaction, so the hidden information cannot be selected, copied, searched or recovered.

Every page is shown, and you can draw as many redaction boxes as you need across any pages before exporting a single redacted PDF. Take a moment to cover everything sensitive, including headers, footers and reference numbers that are easy to overlook.

The cost of true redaction is that the output pages are image-based, so their text is no longer selectable and the file can be somewhat larger. That is the price of a guarantee that the redacted content is actually gone.

It runs entirely in your browser using pdf.js, so confidential documents never leave your device. That is essential for exactly the files you would redact: contracts, bank statements, payslips, IDs, medical letters and anything you must share without leaking the details underneath.