Protect PDF
Add AES-256 password protection — without the file going anywhere.
Processed on your device — nothing is uploaded. Works offline.
Don't trust us — test us
Load this page, then turn off your wifi. The tool keeps working, because your file is processed by your own browser — there is no server involved and nowhere to upload to. How to verify this yourself →
Frequently asked questions
What encryption is used?
AES-256, the strongest encryption the PDF standard supports, applied by qpdf — the same open-source engine used in professional PDF pipelines — compiled to WebAssembly and running in your browser.
What happens if I forget the password?
The file is genuinely encrypted, and we never see or store anything — there is no reset. Keep the password somewhere safe, like a password manager.
Is there a file size limit?
No hard limit — your device's memory is the ceiling. Files up to a few hundred MB work well on a typical laptop. Very large files may be slow or fail on low-memory devices; nothing is ever truncated silently.
Do I need to create an account?
No. No account, no email, no cookies. The free tools are simply free.