Protect PDF with Password
Pick a PDF, set a password to open it, optionally an owner password, and tick the permissions readers should have. The encrypted file is built on your device.
About this tool
PDF security has two passwords. The user password is needed to open the file at all. The owner password unlocks everything, including changing the permissions; if you leave it blank, the open password is used for both. Permissions such as printing or copying are enforced by well-behaved viewers, so treat them as guidance rather than a guarantee.
The file is encrypted with AES-256, the strongest scheme the PDF standard defines, using the pdf-lib library entirely in your browser. There is no recovery if you forget the password: the content is encrypted with a key derived from it, so keep the password somewhere safe.
Frequently asked questions
- Which encryption is used?
- AES-256 as specified in PDF 2.0. It opens in Adobe Reader, Preview, Chrome, Firefox and every current viewer.
- What is the difference between the two passwords?
- The open password is required to view the file. The owner password additionally lifts the permission restrictions. If you set only one, it serves both purposes.
- Can I protect a file that already has a password?
- Remove the old password with the unlock tool first, then protect it again with the new one.
- Is the file uploaded?
- No. Encryption happens in your browser and the password never leaves your device.