Protect a PDF with a password
To password-protect a PDF, choose the file, type the password twice and press Protect. The PDF is encrypted with AES-256 on your device and can only be opened with that password.
- ๐ Runs on your device
- โค 0 bytes uploaded
- ๐ด Works offline
- โ Free, no sign-up, no watermark
How to use Protect PDF
- Choose the PDF file.
- Type the password you want, twice.
- Optionally set permissions such as printing and copying.
- Press Protect PDF and download the encrypted file.
About Protect PDF
Nolo encrypts with pdf-lib: every text, image and font stream in the file is encrypted with a random key that is itself protected by your password.
If you leave the owner password empty, Nolo sets a long random one. That way the permissions you choose cannot be removed by someone who only knows the open password.
Is it private?
Yes. Protect PDF runs entirely in your web browser using your device's own processor. Your files are never uploaded to Nolo or anyone else, and the page cannot send them anywhere: its security policy only allows it to talk to nolotools.com, which has no place to receive files. Results are kept encrypted on your device for 60 minutes in Your files, then deleted automatically, or straight away with Delete all. How Nolo works.
Questions and answers
Is my PDF or my password uploaded?
No. Encryption happens in your browser. Neither the file nor the password leaves your device, and Nolo never sees either.
How strong is the protection?
The PDF is encrypted with AES-256 (PDF 2.0 standard security, revision 6). With a long password that is not used elsewhere, it cannot practically be broken.
What if I forget the password?
Nobody can recover it, Nolo included, because the password is never stored anywhere. Keep it in a password manager.
Do the permissions really stop printing or copying?
Most PDF apps respect them, but some ignore them. Only the open password truly protects the content; treat permissions as a request to well-behaved apps.
Will older PDF readers open the file?
AES-256 is supported by Adobe Acrobat and Reader X (10) and later and by all current browsers and PDF apps. Very old readers may not open it.
How do I remove the password later?
Use Unlock PDF and type the password.