Password-protect a PDF with AES-256 encryption.
Encryption happens entirely in your browser. Your file and password never leave your device.
or drag and drop a PDF here
Select or drop the file you want to lock. If it already has an open password, remove that password first with Unlock PDF, then protect it again here with a new one.
Enter a password and confirm it. It must be at least four characters; a longer, unique password is much safer. You will need this password to open the file later — we cannot recover it for you, because we never see it.
Click Encrypt & Download. The new PDF uses AES-256 encryption and will ask for the password in any standard reader. Open the download once to confirm it locks as you expect, and store the password somewhere you will find it.
Encryption runs in your browser. The PDF and the password you type are not uploaded and are not stored by AllOnePDF, so the secret never has to travel to a server to be applied.
No. The password is used in your browser to encrypt the file and is not sent to us. We cannot reset it if you forget it.
The download is protected with AES-256 and will require the password to open in a standard PDF reader.
PDF/A does not allow encryption. This tool strips that flag from the metadata so the file can be locked, and only rebuilds the document from its pages if that still fails.
If the file already has a password, unlock it first. Otherwise, use Print → Save as PDF in your reader to make a fresh PDF, then encrypt that copy.
This tool sets an open password: the file cannot be read without it. It is not a permissions-only lock.
No. Encryption happens on your device. The locked PDF is then downloaded locally.