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Protect PDF.

Encrypting a document by uploading it — together with its new password — to someone else’s server defeats the point. This tool runs qpdf, the same engine many professional tools use, compiled to WebAssembly inside your browser: the PDF is encrypted with AES-256 locally, and neither the file nor the password is ever transmitted. The result opens in any standard PDF reader that asks for the password.

Drop PDF files here, or browse

Files stay on your device — nothing is uploaded.
i. Type the password you want the PDF to require.
ii. Drop one or more PDFs onto the box above.
iii. Each file is encrypted locally with AES-256 by qpdf compiled to WebAssembly.
iv. Download the protected PDFs. Neither the files nor the password left your device.
More tools: Unlock PDFRemove PDF metadataRedact PDF

Read the guide: How to Password-Protect a PDF (AES-256) Without Uploading It

Frequently asked questions

How strong is the encryption?

AES-256 — the strongest standard PDF encryption, the same level Acrobat applies. Anyone opening the file needs the password.

Is my password sent anywhere?

No. The password is used inside your browser tab to derive the encryption keys and is never transmitted or stored. You can verify with the network tab or airplane mode.

What if I forget the password?

Nobody can reset it — there is no account and no copy of your password anywhere. That is the point of real encryption, so store the password somewhere safe.

Will the protected PDF open in normal readers?

Yes. This is standard PDF encryption — Acrobat, Preview, browsers and phones all prompt for the password and open it normally.

Embed this tool

Add this free, no-upload tool to your own site with one line:

<iframe src="https://fileanvil.com/embed/protect-pdf/" width="100%" height="480" style="border:1px solid #ddd;border-radius:12px" title="Protect PDF with a Password"></iframe>