What's the difference between the open password and owner password?

The open password is required just to view the PDF at all. The owner password only gates changing the permissions later — a PDF can have one, the other, or both.

Is this real encryption, or just a permissions flag?

Real encryption — AES-256, the current PDF standard — is applied when you set an open password. Permission restrictions without an open password are still written into the file the same way any PDF tool declares them, but note that permissions alone are advisory: conforming readers respect them, but they're not a substitute for an open password if the content itself must stay confidential.

Does encrypting happen on my device?

Yes. The PDF is encrypted directly in your browser tab using the Web Crypto API — neither the file nor the password is ever sent anywhere.

Protect PDF

Add an open password, an owner password, or restrict printing/copying/editing — encrypted with AES-256, entirely on your device.

Read the Protect PDF guide

Processed on your device

Upload a PDF to Protect PDF

Drag and drop or click to select

Once protect pdf is done, you can send the result straight into another tool — merge, sign, compress, and more — without downloading and re-uploading.

Works well with

Redact PDF

Draw a box over anything sensitive and it's genuinely deleted, not just painted over.

Unlock PDF

Remove a PDF's editing restrictions or its open password.

Remove PDF Metadata

See what's embedded — title, author, software, timestamps — and strip it all in one click.

Protect PDF

Works well with

Common questions

What's the difference between the open password and owner password?

Is this real encryption, or just a permissions flag?

Does encrypting happen on my device?