The encryption happens on your device, so the file and the password never travel anywhere.
Choose a password, and only people who know it can open your PDF. The file is encrypted with AES-256 on this device, so the document and the password never travel anywhere. It is free.
How to password protect a PDF, step by step
- Open the PDF by dropping it on the page or pressing Choose a PDF.
- Type a Password to open, and type it again to confirm. Use Show passwords to check what you typed.
- Choose the Encryption: AES-256, or AES-128 for very old PDF readers.
- If you want, limit Printing, Copying text, Editing pages and Comments and forms, and add a Permissions password.
- Press Download locked PDF.
How the password protects your PDF
Your PDF is encrypted with AES-256, the standard used by Adobe Acrobat, Preview, Chrome, Edge and every current PDF app. Without the password the pages, text and pictures inside are scrambled, and anyone who opens the file is asked for the password first. AES-128 is offered for very old readers that cannot open AES-256 files.
Pick a password you will remember
Nobody can open the locked copy without the password, and that includes us: there is no reset link and no back door. Keep the original file somewhere safe, or store the password in a password manager. Use at least 8 characters. Longer is stronger, so a short sentence or a few unrelated words beat a single word with symbols.
Limits on printing, copying and editing
You can switch off printing, copying text, editing pages, and comments and forms. Most PDF apps respect these limits, but they are a request rather than a lock: only the open password truly keeps people out. A permissions password lets you change the limits later in apps such as Acrobat.
When to lock a PDF
- Sending contracts, payslips, tax papers or medical records by email.
- Sharing a CV, ID scan or application with a single person.
- Storing sensitive documents in cloud folders.
- Sending a draft to a client that is not ready for wider viewing.
Send the password through a different channel from the file, such as a text message. To remove a password you know from a PDF, use Unlock PDF.
Privacy
The encryption happens in your browser. Your PDF and your password are never uploaded, logged or stored, and the locked copy is saved straight to your device.
Questions
What if I forget the password?
It cannot be recovered. Keep the original file and store the password safely.
Is AES-256 safe?
Yes. It is the strongest encryption available for PDFs and is supported by every current PDF app.
Will it change my original?
No. You download a new locked copy.