Can You Password-Protect a PDF?
Yes — but how strong the protection is depends on the tool. Desktop apps and paid editors apply real encryption; many free browser tools only restrict editing, not open the file.
Two kinds of PDF passwords
- Open password — required before the file opens (real encryption).
- Permissions password — lets the file open but blocks print/edit/copy.
What tools can actually do it
| Tool | Open password | Permissions only | Price |
|---|---|---|---|
| Adobe Acrobat | Yes | Yes | Paid |
| PDF24 (desktop) | Yes | Yes | Free |
| PDFzen (browser) | No | Removes only | Free |
If you just need to stop casual edits
Our Unlock tool removes restrictions from a file you already own; we don't add new passwords because browser-side PDF encryption isn't reliable. For true protection, use a desktop app.
What we verified
We tested PDFzen's unlock on a permissions-restricted file we created — it stripped the restriction so the file opened fully editable. We deliberately do not offer "add password" because PDF-lib's encrypt option is ignored by readers, which would mislead users.
FAQ
Can you password protect a PDF for free?
Yes with PDF24 (desktop) or Acrobat's trial; free browser tools usually can't apply real encryption.
Is a PDF password secure?
A strong open password is secure; permissions-only passwords are easy to remove.
Can PDFzen add a password?
No — we're honest that browser-side encryption isn't reliable, so we only remove restrictions.