Password protect a PDF
Add a real password and AES-256 encryption to a PDF, with separate controls for printing, copying and editing. The password is set and applied entirely in your browser — it never leaves your device.
Encrypt PDF
Real AES-256 · password + printing/copying/editing permissions
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How to Encrypt PDF
- Add your PDF. Drag the file onto the drop zone.
- Set a password. Enter and confirm the password that will be required to open the file.
- Choose permissions. Decide whether printing, copying and editing should stay allowed once the file is locked.
- Encrypt and download. The tool renders each page, rebuilds the document with real AES-256 encryption, and starts the download.
Why this tool renders each page as an image
Most tools on this site rewrite a PDF's internal structure directly using pdf-lib — that library can merge, split and stamp pages, but it has no way to write an encryption dictionary into the file it produces. Nothing in the browser-side JavaScript ecosystem does both structural edits and encryption at once.
The library that can genuinely encrypt a PDF (pdfkit) can only build a document from scratch — it has no way to read an existing one. So this tool bridges the two: it renders every page of your PDF to an image using the browser's own PDF engine, then feeds those images into pdfkit to build a brand new, AES-256-encrypted document.
The honest tradeoff is that the output is a sequence of page images rather than the original selectable text. It opens identically in any PDF reader and prints at full quality, but text can no longer be selected, searched or copied out — which is exactly what a password-protected file is usually for in the first place.
What the permission checkboxes actually control
A PDF's password can require unlocking the whole file (a user password) or only restrict what a reader is allowed to do once it's open (owner permissions) — this tool sets both to the same password, so the file is genuinely locked rather than just flagged.
Printing, copying and editing are separate flags inside that encryption dictionary. Turning one off doesn't remove the ability from every PDF reader — well-behaved software respects it, which covers the overwhelming majority of real-world use.
Frequently asked questions
Is this real encryption, or just a password prompt?
Real encryption — AES-256, the current standard (PDF 1.7 Extension Level 3). Anyone without the password cannot open the file in any compliant reader, not even to view a page.
Why does the output say the text isn't selectable anymore?
Because the encryption library used here (pdfkit) can only build a PDF from images and drawing commands, not from another PDF's text layer. Each page is rendered as a high-quality image first, then locked — so the pages look identical but the underlying text is gone.
Will the file size change?
Usually it grows, since text-based pages become images. A short text document might go from a few hundred KB to a few MB; a scanned PDF that was already image-based will barely change.
What happens if I forget the password?
The file cannot be opened. There is no recovery mechanism, by design — a password only protects data if there's no back door around it.
Is my password sent anywhere?
No. The password is used locally to build the encrypted file and is never transmitted — there's nowhere for it to go, since this tool has no server component at all.
Can I remove the password later?
Yes, using the Remove Password tool, which needs the working password to decrypt the file back to normal.
Does this work on scanned PDFs?
Yes — since scanned pages are already images, encrypting them adds no visible quality loss at all.
Related tools
Related reading
Longer guides covering the part this tool does not.