All tools › PDF security › Protect PDF
Protect PDF
Put a real password on a PDF, without uploading it.
or drop a file here · paste with Ctrl+V
PDF · AES-256 · up to 200 MB
Protected on your device. Nothing is uploaded.
Ready to protect
Set a password in the sidebar. The copy is encrypted with AES-256; the original file is untouched.
Encrypting…
Your PDF is protected
How to password-protect a PDF
To protect a PDF, drop the file in, type a password twice, and press Protect PDF. The copy is encrypted with AES-256 — the same standard banks and law firms ask for — and opens with that password in any reader. You can also decide whether printing and text copying stay allowed. The encryption happens in your browser.
Add your PDF
Choose a file or drop it in. Nothing is encrypted until you press the button.
Set the password
Type it twice. Optionally allow printing or copying; leave them off to lock the content down.
Protect and download
You get an AES-256 encrypted copy. Keep the password safe — it cannot be recovered.
What Protect PDF does and does not do
It encrypts the document with AES-256 and sets an open password, so readers ask for it. Permissions for printing and copying are advisory: most viewers honour them, some ignore them. There is no password recovery, and no way to open the file without it. The original file is never modified. Files are encrypted on your device and never uploaded.
Private by design
Encryption runs in your browser with WebAssembly. Your PDF and your password never leave your device.
Questions
How strong is the protection?
AES-256, the current standard for PDF encryption. It is the same strength used for sensitive business documents.
Can I still print the protected file?
That is your choice at protection time. Leave “Allow printing” ticked and readers will permit it; untick it and most readers block it.
What happens if I forget the password?
The file cannot be opened. There is no recovery and no backdoor — that is what makes the encryption meaningful.
Is my password uploaded?
No. It is used in your browser to derive the encryption key and is never sent anywhere.
Will it open in Acrobat, Preview and Chrome?
Yes. AES-256 is part of the PDF standard, so any current reader can open it with the password.
Can I protect only some pages?
Encryption applies to the whole document. Split the file first if only part of it should be locked.
Does protecting change the pages?
No. The pages are encrypted, not re-rendered, so content is unchanged apart from the lock.
Why does this page have no ads?
Encryption needs cross-origin isolation, which blocks third-party resources. We keep the tool and drop the ads rather than the other way round.
Read: Are online PDF tools safe?