Password protect a PDF
Password protect a PDF so only people with the password can open it. Files are encrypted with AES-256 by qpdf, a long-running open-source PDF library, and it all happens on your own device.
or drop a file here
One PDF, up to 250 MB.
Processed on your device. Nothing is uploaded.
How to password protect a PDF
Open the PDF
Choose the file you want to lock.
Set a password
Type it twice. The meter tells you whether it’s strong enough.
Permissions (optional)
Decide whether people can print, copy or edit.
Encrypt and send
Download the protected copy. Send the password separately, not in the same email.
How the protection works
AES-256
The strongest encryption the PDF standard has. Any up-to-date PDF reader opens it, phone apps included.
Proven code, not ours
We don’t write our own encryption. qpdf, compiled to run in your browser, does the work.
Your password stays put
It’s used inside this tab to encrypt the file and then discarded. It never reaches us.
Picking a password that actually helps
AES-256 is only as good as the password on it. Go for at least 12 characters, or three or four unrelated words strung together. Skip names and birthdays, or anything printed in the document itself.
Permissions (no printing, no copying) are respected by mainstream readers, but the encryption doesn’t enforce them, so treat them as a polite request. The open password is the real protection. For more, see how to password protect a PDF on Mac and Windows, or our PDF privacy guide.
Privacy and security
We can’t recover a forgotten password. It isn’t sent to us or stored anywhere, so if it’s lost, so is access to the file. Keep it in a password manager.
Read more in our privacy policy.
Protect PDF FAQs
How secure is AES-256?
With a strong password it isn’t realistically breakable by guessing. The weak point is almost always a short or obvious password.
Can I take the password off later?
Yes, if you know it, using Unlock PDF.
What’s the permissions password for?
Whoever holds it can change the permissions. Leave it blank and we generate a long random one and throw it away, so the permissions can’t be changed without removing the encryption altogether.