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Protect PDF

Add a password to a PDF online with AES-256 encryption and choose whether people may print, copy or edit it. Encrypted in your browser, never uploaded.

Runs in your browser · Nothing uploaded · No sign-up

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About the Protect PDF

Protect PDF adds a password to a PDF so it cannot be opened without it, using AES-256 encryption, the strongest the PDF format supports. You can also stop people from printing, copying text or editing the file after they open it. Encryption is done by QPDF, compiled to WebAssembly and running in your browser, so the document and the password are never sent anywhere.

PDFs are processed in your browser (pdf-lib, PDF.js and, for passwords, QPDF compiled to WebAssembly), so contracts, invoices and scans never leave your device.

How to use the Protect PDF

  1. Choose the PDF you want to protect.
  2. Enter the password people will need to open it, twice.
  3. Optionally turn off printing, copying or editing, and set a separate permissions password.
  4. Click Protect PDF and download the encrypted copy. Keep the password safe: it cannot be recovered.

Common mistakes

  • Sending the password with the file. If the password travels in the same email as the PDF, anyone who gets the email can open it. Share the password by another channel, such as a call or a message.
  • Using the same password for opening and permissions. Whoever can open the file would also be able to lift the restrictions. Use a different permissions password.
  • Relying on restrictions for secrets. Print and copy restrictions do not encrypt anything extra. For confidential content, the password to open the file is what protects it.

Works well with the Protect PDF

Frequently asked questions

How secure is the password protection?

The file is encrypted with AES-256 (PDF 2.0 security), so its contents cannot be read without the password. The weak point is the password itself: a long passphrase of several unrelated words is far safer than a short word with numbers.

Can people still print or copy if I turn it off?

Reputable readers such as Adobe Acrobat, Chrome and Preview respect the restrictions, but they are a policy stored in the file, not encryption of the content. Anyone who can open the PDF could take screenshots, so restrictions deter casual copying rather than stop it.

Will every PDF reader open the protected file?

Yes, any current reader opens AES-256 PDFs: Adobe Acrobat and Reader 9 or later, Chrome, Edge, Firefox, macOS Preview and mobile readers. Only very old software from before 2008 cannot.

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