What is the owner password for?

An optional second password that grants full permissions (printing, editing) regardless of the user password. Leave it blank if you don't need that distinction.

How strong is this encryption?

Uses the real PDF standard security handler (128-bit or 256-bit AES, your choice) via the qpdf engine - the same encryption format Adobe Acrobat and other PDF tools implement.

Does this tool upload my PDF anywhere?

No — the file is encrypted entirely in your browser using a WASM build of qpdf.

Protect PDF with a Password

Add a password to a PDF so only someone who knows it can open the file.

Choose a PDF

Drop a file, paste, or click to browse

Up to 50 MB.

Files never leave your device.

Related tools

Unlock PDF (Remove Password)
Merge PDF
Extract PDF Pages
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How it works

1
Choose a PDF

Up to 50 MB.
2
Set a password

An optional separate owner password too.
3
Download the protected PDF

Opening it now requires the password you set.

FAQ

What is the owner password for?: An optional second password that grants full permissions (printing, editing) regardless of the user password. Leave it blank if you don't need that distinction.
How strong is this encryption?: Uses the real PDF standard security handler (128-bit or 256-bit AES, your choice) via the qpdf engine - the same encryption format Adobe Acrobat and other PDF tools implement.
Does this tool upload my PDF anywhere?: No — the file is encrypted entirely in your browser using a WASM build of qpdf.