Password-protect a PDF
Add an AES-256 password to a PDF and choose whether readers may print, copy or edit it.
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Payslips, medical reports, contracts and ID copies should not travel as open PDFs. Set a password and the file is encrypted with AES-256, the strongest encryption the PDF standard offers, so it cannot be opened without the password in Acrobat, Preview, Chrome, Edge or any modern reader.
You can also restrict what people who open it may do: printing (full, low resolution or not at all), copying text, editing, commenting, filling forms and rearranging pages. An optional separate permissions password lets you lift those restrictions later without giving it to readers.
Encryption uses qpdf, the widely used open-source PDF tool, compiled to WebAssembly and run in your browser. Encrypting a confidential file on a website that uploads it defeats the purpose; here the file never leaves your device.
How to use it
- Choose a PDF.
- Type the password twice (and, optionally, a separate permissions password).
- Choose what readers may do: print, copy, edit, comment, fill forms.
- Click Protect PDF and download the encrypted file. Keep the password safe.
Frequently asked questions
Are my files uploaded?
No. The first time you use the tool your browser downloads the processing engine from this site, like any other part of the page; your PDF itself is read and processed on your device and never sent anywhere.
How strong is the protection?
AES-256 with the PDF 2.0 (revision 6) password scheme. The practical strength is the password itself: use a long phrase, not a short word.
What if I forget the password?
It cannot be recovered, by us or anyone else: nothing is stored. Keep an unprotected original somewhere safe, or save the password in a password manager.
Do the print and copy restrictions really stop people?
Mainstream readers honour them, but they are a request built into the file rather than hard protection. The open password is what truly protects the content.
Can I protect a PDF that is already protected?
Remove the existing password first with Unlock PDF (you need to know it), then protect the unlocked copy with the new settings.
Related tools
- Unlock a PDFRemove the password and restrictions from a PDF you own, using its password. No password cracking.
- Redact a PDFBlack out text and images for real: covered pages are rebuilt as images so nothing remains underneath.
- Add a watermark to a PDFStamp text or an image on PDF pages: opacity, rotation, seven positions or tiled, page ranges.
- Compress a PDF to a smaller file sizeShrink scanned PDFs to a target size (such as 200 KB) or by level, on your device. The result is image-based.
- Random password generatorRandom passwords from crypto.getRandomValues, 8 to 64 characters, with the entropy in bits and a strength label.