ProtectPDF

Add a password to your PDF so only the people you choose can open it.

Drop your PDF here…
  • Private
  • AES-256
  • Free

Before sending a contract, bank statement or personal document by email, add a password. This tool encrypts the PDF with AES-256 in your browser: neither the file nor the password leaves your device. The recipient will need the password to open it.

How does it work?

  1. Choose your PDF

    Drop or choose the file. It opens in your browser — nothing is uploaded.

  2. Set a password

    Pick a password you'll remember. It's used to encrypt the file.

  3. AES-256 encryption

    The qpdf engine encrypts the PDF with 256-bit AES — the same standard banks use.

  4. Download the protected file

    The new PDF will ask for the password every time someone opens it.

Features

  • AES-256 encryption

    The highest encryption level for PDF, compatible with Adobe Acrobat and all modern readers.

  • Open password

    Anyone without the password cannot see the PDF contents.

  • Content stays intact

    The PDF stays exactly the same inside — pages, text, links and forms.

  • Free, no signup

    No accounts, no watermarks, unlimited uses.

Use cases

  • Send sensitive documents

    Protect contracts, invoices or legal documents before emailing them.

  • Share private files

    Share a PDF via WhatsApp or cloud storage and send the password separately.

  • Meet legal requirements

    Some processes require encrypted document submission.

  • Archive personal information

    Protect receipts, certificates or records with a password on your disk.

How is it different?

Most online tools upload your PDF and password to their servers. Here all encryption runs in your browser.

  • vs Adobe Acrobat Pro: Adobe charges a monthly subscription. Here it's free and the PDF is never uploaded.
  • vs iLovePDF / Smallpdf: Here the file never leaves your device. All encryption runs in the browser.

Frequently asked questions

What encryption does it use?

256-bit AES, the highest standard for PDF. Compatible with Adobe Acrobat, Chrome, Firefox and all modern readers.

Can the password be removed later?

Yes, with the correct password you can use our Unlock PDF tool.

Does it work with already protected PDFs?

No. If the PDF already has a password, unlock it first and then set a new one.

Is my file uploaded anywhere?

No. Everything runs in your browser with qpdf compiled to WebAssembly. Neither the PDF nor the password leaves your device.

Is there a file size limit?

Up to 200 MB. Encryption is fast — a few seconds even for large files.