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Password protect a PDF

Encrypt a PDF with AES-256 so it can only be opened with the password you set. The password and the file stay in your browser; nothing is uploaded.

Choose files

Tap to pick files from your device

Free plan: 1 file per job. Each file up to 20,000,000 bytes and 50 pages. All selected files together up to 100,000,000 bytes. Encrypted and digitally signed PDFs are not accepted.

This operation runs in your browser. Your files are not uploaded for processing.

Result

The result appears here after you run the tool.

How to password protect a PDF

  1. 1

    Select or drop a PDF file.

  2. 2

    Type a password, then type it again.

  3. 3

    Protect the file.

  4. 4

    Download the encrypted PDF.

What this tool does

  • AES-256 encryption
  • Opens in current versions of Adobe Acrobat Reader and in browser PDF viewers
  • Password never leaves this tab
  • No permission restrictions that a second password could lift
  • Reads the file signature instead of trusting the file extension.
  • Copies real pages. Nothing is rasterized and no page is re-rendered.
  • Refuses encrypted PDFs instead of working around the protection.
  • Refuses digitally signed PDFs, because saving them again would break the signature.
  • Reports the measured size of the file your browser produced.

Questions about Protect PDF with a password

What happens if I forget the password?
The file cannot be opened, and this site cannot help: the password is not stored or sent anywhere. Keep it somewhere safe before you delete the unprotected original.
How strong is the protection?
The content is encrypted with AES-256, so the protection depends on your password. A short or common password can be guessed by trying many candidates, so use a long one.
Will it open on any device?
Current PDF readers support AES-256, including Adobe Acrobat Reader, the viewers in Chrome, Edge, Firefox and Safari, and the Files and Preview apps on Apple devices. Very old readers from before 2008 cannot open it.
Are my files uploaded to a server?
No. This tool runs inside your browser tab, so the file bytes are read and written on your own device and are never sent to us for processing. Closing the tab discards everything, which is also why results cannot be restored after a reload.

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