Zokilos

Protect PDF

Choose a password, download a locked copy that requires it to open

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Click to choose a file, or drag it here
.pdf only — one file at a time
Passwords don't match.

There's no way to recover a lost password — save it somewhere safe.

What Does This Tool Do?

It adds password protection to a PDF, so it can't be opened in any PDF reader without the password you choose. Upload the file, set a password, and download the locked copy.

Losing this password means losing access to the file — there's no recovery, by this tool or anyone else. Keep it somewhere safe.

How to Password-Protect a PDF Online

1

Upload the PDF you want to lock.

2

Choose and confirm a password.

3

Press "Protect PDF" and download the locked file.

Why Password-Protect a PDF?

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Sensitive documents

Add a layer of protection before emailing contracts, invoices, or records.

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Shared drives

Keep a file readable only to people you give the password to, even on shared storage.

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Sending outside your org

Require a password before an external recipient can open the file.

Does This Change the PDF's Content?

No. Every page, image, and piece of text is copied over exactly as it was — only an encryption layer requiring your password is added on top.

Is It Safe to Protect a PDF Online?

Yes — your file and the password you set are processed in memory during the request and never written to disk or stored anywhere. No account or sign-up required.

Limitations of This Tool

  • Can't protect a PDF that's already password protected — remove the old password first
  • No password recovery if you lose what you set

Benefits of Using This Tool

  • Adds standard PDF password protection in one step
  • No quality or formatting changes to the PDF itself
  • Free, runs in your browser session, no sign-up

Frequently Asked Questions

What kind of password protection does this add?

Standard PDF open-password encryption — the file requires that password to be viewed in any PDF reader. The same password is set as both the user (open) and owner (permissions) password.

What if I lose the password?

There's no recovery — the whole point of the protection is that the file can't be opened without it, including by this tool. Save it somewhere safe before you close this page.

Can I protect a PDF that's already password protected?

No — remove the existing password first (with a tool like our PDF Password Remover), then protect it with the new one.

Does adding a password change the PDF's content?

No. Every page, image, and piece of text stays exactly as it was — only an encryption layer requiring the password is added.

Is it safe to protect a PDF online?

Yes — your file and the password you choose are processed in memory during the request and never written to disk or stored anywhere. No account or sign-up required.

Need to remove a password instead? Try PDF Password Remover.