Lock a PDF Behind a Password (AES-256)
Require a password to open a PDF using AES-256 or AES-128, and optionally restrict printing or copying.
Free, with no sign-up and no watermark. The file is processed in your browser and never uploaded.
Add a password that's needed to open a PDF, and choose what people can do once it's open. Files are encrypted with AES-256 by default; AES-128 is available for older readers.
You can also set an owner password and switch off permissions such as printing or copying. Those permissions are honoured by mainstream PDF readers, but they aren't as strong as the open password itself.
Step by step
- Upload the PDF: Already-protected files are decrypted first (you'll be asked for their password).
- Set the password: Enter it in Password to open and again in Confirm password.
- Optionally set an owner password: Needed to change permissions later. If left blank, a random one is generated.
- Choose permissions: Untick anything you want to forbid: printing, copying, editing, comments, filling forms or page assembly.
- Encrypt: Click Password Protect. The file downloads with "-protected" in its name.
Handy for
Sending personal data
Protect payslips, medical letters or ID copies before emailing them.
Client documents
Share contracts and reports that only the client can open.
Stopping casual copying
Disable copying and printing on review copies.
Archives on shared drives
Keep sensitive files unreadable without the password.
Good to know
Send the password through a different channel from the file — for example by text message if the PDF goes by email.
Use a long passphrase; the open password is what actually protects the content.
If you leave the owner password blank, keep the original unprotected file in case you need to change permissions.
Questions
Are my files uploaded anywhere?
No. The file is read and processed by JavaScript running in your browser tab. Nothing is sent to a server, and the result is created on your device.
What is the difference between the open password and the owner password?
The open (user) password is needed to view the file and is enforced by encryption. The owner password controls permissions like printing; those are rules that readers choose to respect.
Which should I choose, AES-256 or AES-128?
AES-256 for anything current. Choose AES-128 only if a recipient uses very old software (before about 2008) that can't open AES-256 files.
Can I recover the file if I forget the password?
No. Keep the password somewhere safe, or keep an unprotected original.
Does encryption change the content?
No — text, images and layout are unchanged.
Further reading
- PDF Passwords: How to Add, Remove and Unlock Them — Learn how a PDF's open and permissions passwords differ, add AES-256 protection, and remove a password you know or lift print and copy limits.
More Protect & Redact tools
- Remove a Known PDF Password — Enter the password you know and save a copy of the PDF that opens without one, with text and links kept.
- Allow Printing & Copying in a PDF — Lift print, copy and edit restrictions from a PDF you're allowed to change, keeping its text and quality.
- Find & Redact Personal Data — Find emails, phones, PAN, Aadhaar, cards, IFSC, GSTIN and IBAN in a PDF, review each match, and redact it.
- Test a PDF for Leaky Redactions — Test whether text under black boxes or hidden on blank areas is still readable, and make a properly redacted copy.
- Check a PDF for Hidden Data — List a PDF's metadata, form data, attachments and scripts, and find emails, phones, PAN, Aadhaar or card numbers.
- SHA Hashes for Files — Compute SHA-256, SHA-384, SHA-512 and SHA-1 hashes of a file and compare them against a hash you paste.