Protect a PDF
Protecting a document is not one feature. Passwords, redaction and watermarking solve different problems, and redaction done badly leaves the original text recoverable underneath.
61 tools here do less than the name of this job suggests, and each one's profile says what it actually does. That sentence is on the profile rather than repeated on every row.
61 options · Sources read 16 October 2026 · Redaction verdicts on this site are recorded from the vendor’s own documentation unless the profile says we tested it. Several entries carry a tested verdict from a document we built for the purpose.
- What it takes, and what it produces
- In: a PDF. Out: a PDF with encryption, and usually permissions attached to it.
- What limits it
- What the encryption protects varies by algorithm and by version, and permission restrictions are advisory in some readers rather than enforced. The record says what the vendor claims, which is not the same as what every reader honours.
Protect tools: controls, file handling and cost
These are different ways to do the same job. The order does not indicate quality, and where we have not checked something the row says so rather than guessing.
- 61
- tools handle this job
- 33
- keep the file on your device
- Observed by us, or no server anywhere in the path. Of the other 28: 4 upload your file; 19 process some versions on your device and run others on a server; 3 are documented as staying local but have not been tested; 2 run on a server you provide.
61 tools for protecting
Ordered by relevance to this job, not by payment. Our overall ranking is in the full index.
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Our pick 2: A command-line workhorse under a permissive licence. Local, scriptable, and the engine underneath several other tools here.
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Our pick 5: A Go library and CLI for validation, encryption and assembly. Local, and honest enough to say its PDF 2.0 validation is basic.
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Our pick 1: Run it yourself and nothing leaves your network. Redaction deletes the matching text without flattening the page - we tested that on our own instance.
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Our pick 4: Local Python around qpdf, and the project whose own documentation says programmatic redaction cannot be reliable. That warning is the most useful sentence in this index.
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Our pick 3: Desktop splitting and merging with no upload, and a policy that states plainly that no PDF content is sent to their servers.
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Our pick 7: Free, open source, no subscription and no bundled software. The reader to install when you want nothing else installed.
Every listing here is a real product with a real website, checked for whether it is still working. Nothing on this page is paid for and no placement can be bought. Where we have not verified something, the row says so rather than guessing.
Choosing between passwords, redaction and watermarking
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Passwords and permissions
A password stops the file being opened and is enforced by encryption. Permissions that say "do not print" or "do not copy" are flags a reader may simply ignore, and they protect nothing on their own.
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Removing content, rather than covering it
Drawing a black rectangle over text leaves the text in the file. It is a frequent and serious mistake with PDFs, and it is invisible in every screenshot of the result.
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Watermarking
A label for provenance or a draft marker. It is not a protection: a watermark can be removed by anybody who can edit the file.
Encryption is not redaction. Anybody with the open password sees everything in the document, including anything that was only covered by a rectangle.
Check the result
- - If you redacted something, select the area and copy it, then paste into a text editor. If the words appear, they are still in the file.
- - Alternatively run the redacted file through a text extractor and search for the phrase you removed. If the search finds it, the redaction failed.
- - For a password, check the file opens in a different reader and that the password is genuinely required rather than only requested.
- - For permissions, test one that matters. If printing is disallowed, try printing.
Sources and scope
Every fact on this page comes from a vendor's own page. Each profile records the URL we read, the date, and the SHA-256 of the text, so a reader can check the bytes.
- Apryse 2 sourced claims, read 22 September 2026
- PyMuPDF 3 sourced claims, read 22 September 2026
- Bluebeam Revu 2 sourced claims, read 22 September 2026
- Foxit PDF Editor 2 sourced claims, read 22 September 2026
- Power PDF 2 sourced claims, read 22 September 2026
- Adobe Acrobat 4 sourced claims, read 21 September 2026
- Adobe PDF Library 2 sourced claims, read 1 October 2026
- Aspose.PDF 2 sourced claims, read 22 September 2026
- IronPDF 2 sourced claims, read 22 September 2026
- Nutrient 2 sourced claims, read 22 September 2026
- PDF Studio 2 sourced claims, read 22 September 2026
- Syncfusion PDF 2 sourced claims, read 22 September 2026
- Wondershare PDFelement 1 sourced claim, read 22 September 2026
- iText 2 sourced claims, read 22 September 2026
- Master PDF Editor 2 sourced claims, read 22 September 2026
- PDF Architect 2 sourced claims, read 21 September 2026
- pdftk-java 1 sourced claim, read 16 October 2026
- qpdf 1 sourced claim, read 22 September 2026
- Apache PDFBox 1 sourced claim, read 22 September 2026
- Soda PDF 1 sourced claim, read 22 September 2026
- ABBYY FineReader PDF 2 sourced claims, read 21 September 2026
- AvePDF 1 sourced claim, read 22 September 2026
- GroupDocs 2 sourced claims, read 1 October 2026
- iLovePDF 1 sourced claim, read 22 September 2026
- MuPDF.js 3 sourced claims, read 22 September 2026
- PDF2Go 1 sourced claim, read 22 September 2026
- pdfcpu 1 sourced claim, read 16 October 2026
- pdfRest 2 sourced claims, read 1 October 2026
- SetaPDF-Core 2 sourced claims, read 16 October 2026
- Smallpdf 3 sourced claims, read 22 September 2026
- SnackPDF 3 sourced claims, read 22 September 2026
- Spire.PDF 2 sourced claims, read 1 October 2026
- Stirling PDF 1 sourced claim, read 22 September 2026
- Apple Preview 2 sourced claims, read 22 September 2026
- LEADTOOLS PDF SDK 3 sourced claims, read 16 October 2026
- LibreOffice Draw 2 sourced claims, read 22 September 2026
- Nitro PDF Pro 1 sourced claim, read 21 September 2026
- PDFsharp 2 sourced claims, read 22 September 2026
- pikepdf 3 sourced claims, read 22 September 2026
- Qoppa Java PDF SDK 2 sourced claims, read 16 October 2026
- Scanner Pro 2 sourced claims, read 22 September 2026
- MuPDF (mutool) 2 sourced claims, read 22 September 2026
- PDF Candy 3 sourced claims, read 22 September 2026
- PDFsam 2 sourced claims, read 22 September 2026
- ReportLab 2 sourced claims, read 16 October 2026
- SwiftScan 2 sourced claims, read 22 September 2026
- CamScanner 2 sourced claims, read 22 September 2026
- Genius Scan 2 sourced claims, read 22 September 2026
- PDFescape 2 sourced claims, read 22 September 2026
- DocHub 2 sourced claims, read 22 September 2026
- pypdf 1 sourced claim, read 1 October 2026
- SumatraPDF 1 sourced claim, read 22 September 2026
- pdf-redactor 3 sourced claims, read 22 September 2026
- fpdf2 2 sourced claims, read 1 October 2026
- JPedal 2 sourced claims, read 1 October 2026
- PDFlib 2 sourced claims, read 1 October 2026
- Telerik Document Processing Libraries 3 sourced claims, read 22 September 2026
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