PDF redaction

Redact your PDFs without them leaving your servers

NymData detects and redacts the PII in your PDFs.

The PII is removed from the file itself, not just covered by a black rectangle.

The layout is preserved and processing stays on your servers.

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services_agreement.pdf · original

Before: 8 sensitive items, highlighted in red

Professional Services Agreement

Signed on September 14, 2026 in Springfield, Illinois

Section 1. Parties

Between Delta Consulting LLC, represented by Sarah Mitchell, and John Carter, born on May 2, 1981, residing at 1428 Elm Street, Springfield, IL 62704.

Section 6. Payment

Invoices are payable within 30 days. Billing contact: (555) 013-2847, [email protected].

Text readable, selectable, copyable

services_agreement.pdf · after NymData

After: the data is gone from the file

Professional Services Agreement

Signed on in

Section 1. Parties

Between Delta Consulting LLC, represented by , and , born on , residing at .

Section 6. Payment

Invoices are payable within 30 days. Billing contact: , .

Nothing left to search or copy

Data removed, not just covered
Layout preserved
Source file never modified
Metadata erased

How do you redact a PDF that contains personal data?

First, find every piece of PII in the PDF, then remove it from the file itself, not just cover it up.

With NymData, you select a PDF or an entire folder.

The detection engine finds names, addresses, phone numbers, emails, IBANs and other sensitive data.

It creates a redacted copy: the information can no longer be found, by search or by copy and paste.

Processing happens on your servers, and an audit report documents the operation.

The black box trap

Why a black rectangle is not redaction

In many tools, "redacting" a passage means drawing a black rectangle on top of it.

The text stays in the file: a search, a selection or a copy and paste brings it right back.

The document looks protected, but it is not.

It is one of the most common causes of leaks when documents are redacted by hand.

Excerpt from a PDF "redacted" with a black rectangle

The agreement is signed with John Carter, reachable at (555) 013-2847.

Try it: select the black areas with your mouse (or long-press on mobile). The hidden text reappears, just like in a badly redacted PDF.

What NymData does

Real redaction, from the first file to the last

Automatic detection

Names, addresses, emails, phone numbers, IBANs and many other kinds of sensitive data are found in the PDF text, each with a confidence score.

Permanent redaction

Every page that contains sensitive data is rebuilt without that text, with opaque black boxes burned into the page: the information no longer exists in the file.

Layout preserved

Tables, charts, logos and formatting keep their appearance.

Only the sensitive areas are blacked out.

Metadata erased

The author, the creating application and the XMP metadata are erased from every processed PDF, even one with no sensitive data.

Source file never modified

NymData creates a redacted copy in a separate folder, on your servers.

You compare before you share.

Audit report

Every run produces a timestamped report, sealed with a SHA-256 hash: data types detected, items processed, method applied.

Learn more: how NymData works, security and on-premises installation, anonymization vs. pseudonymization. In your industry: healthcare, legal, human resources.

Verification

How to check that a redacted PDF no longer contains the data

In a properly redacted PDF, the data can no longer be found by search, by selection or by extracting the text.

Three simple checks:

Search

Open the PDF and search for the redacted name or phone number (Ctrl + F, or Cmd + F on a Mac).

No result should come up.

Select and copy

Select the blacked-out area and paste it into a text editor.

Nothing should come out.

Extract the text

Convert the PDF to text or to Word with another tool.

The data should not appear anywhere.

In NymData, the before and after view lets you check each document, and the audit report keeps a record of what was processed.

Scope

What NymData processes in your PDFs

SupportedPDF documents: NymData analyzes the document text, detects sensitive data and redacts it while preserving the layout.
Good to knowRedacted pages: To make sure the data is gone, every page that contains some is rebuilt as an image: its text is no longer selectable.; All other pages stay untouched.
SupportedEntire folders: One PDF, or an entire folder with its subfolders: a redacted copy of each document, and one audit report for the whole batch.
SupportedMetadata: The author, the creating application and the XMP metadata are erased from every processed PDF.

FAQ

Frequently asked questions about PDF redaction

Is a black rectangle enough to redact a PDF?

No. A rectangle drawn over the text hides it on screen, but the text stays in the file: a search, a selection or a copy and paste brings it back.

Real redaction removes the information from the file itself.

Does the redacted PDF keep its layout?

Yes. Tables, charts and formatting keep their appearance.

Pages that contain sensitive data are rebuilt as images to make sure the data is gone: their text is no longer selectable.

Can I redact a PDF without uploading it to the cloud?

Yes. NymData is installed on your own servers: detection and redaction happen on-premises.

The PDF is never sent to NymData or to any outside service.

Is the PDF metadata erased?

Yes. The author, the creating application and the XMP metadata are erased from every processed PDF.

Can I redact several PDFs at once?

Yes. NymData processes an entire folder and its subfolders: a redacted copy of each document, and one audit report for the whole batch.

Learn more

See NymData redact a folder of PDFs, live

A demo on a complete NymData installation, identical to the one you will run, with sample documents.

Your files stay with you.