Protect PDF with Password Free — Online

Add a password to a PDF so it requires the password to open. Useful for sharing sensitive documents over email or storage you don't fully trust. Encryption happens in your browser — we never see the password.

How it works

  1. Drop your PDF. Drag the PDF onto the page.
  2. Enter and confirm a password. Pick a strong password. We don't store it, send it anywhere, or have any way to recover it if you forget — it lives only in your browser tab during the operation.
  3. Download the protected PDF. GhostPDF encrypts the PDF in-browser and gives you the locked file. Opening it (in any viewer) will now prompt for the password.

Frequently asked questions

What encryption is used?

AES-256, the standard for modern PDF password protection — the same algorithm Adobe Acrobat uses for its 'high' security setting.

Can it be cracked?

Not by brute force in any practical time, assuming you pick a strong password. Weak passwords (dictionary words, '123456') can be cracked offline by determined attackers. Use 12+ characters with a mix of cases, numbers, and symbols.

Does GhostPDF see or store the password?

No. The password lives only in your browser tab while encryption runs. We have no server, no logs, no fallback — if you lose the password, the PDF is permanently inaccessible.

Will the encrypted PDF work in Adobe Acrobat?

Yes. Standard PDF encryption — any modern PDF viewer (Acrobat, Preview, Foxit, Chrome's built-in viewer) will prompt for the password and decrypt.

Does this stop people copying or printing?

Open-password protection (what we do) requires the password to open at all. Owner-restrictions (preventing print/copy after opening) are not separately configurable here yet.

Free?

Yes. Free forever, no signup, no caps, no watermark.

Related tools

Every GhostPDF tool runs entirely in your browser. Your file is never uploaded — there is no upload endpoint to send it to.