Lock PDF with a Password
Encrypt a PDF with a password using AES-256, free and entirely inside your browser
Drag a PDF file here or click to choose
🔒 All processing happens in your browser — your files are never uploaded to any server
How to use it
- Upload a PDFDrag the file onto the drop zone or click "Choose file". It is read in your browser and never uploaded.
- Choose a passwordType it twice so a typo cannot lock you out of your own document. Anything from a single character upward is accepted, but a long passphrase is far harder to guess.
- Click "Lock PDF"The file is encrypted in your browser with AES-256. Neither the file nor the password ever leaves your device.
- Download and store the passwordOpening the file will now require the password. Save it somewhere safe first — a forgotten password cannot be recovered by anyone, including us.
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Frequently Asked Questions
How strong is the encryption?
It is AES-256 — the strongest encryption level in the PDF standard, the same class used for full-disk encryption, and supported by every modern PDF reader. The password is now the weak point, not the cipher: a short one can still be guessed, so use a long passphrase. For something whose disclosure would be genuinely serious, still prefer full-disk or archive encryption over relying on any PDF password alone.
Does my password get sent anywhere?
No. The encryption happens entirely inside your browser, which is the whole reason this tool can be trusted with a password at all. Nothing — not the file, not the password — is transmitted to us or to anyone else. Close the tab and no trace of either remains.
What happens if I forget the password?
The document is unrecoverable, by us and by anyone else. That is what encryption means. Store the password somewhere safe before you close this page, because there is no reset link and no back door.
Can I remove the password later?
Yes, with our Unlock PDF tool — as long as you know the password. It cannot break one you have forgotten.