Protect a PDF with a password
Encrypt a PDF so that it can only be opened with a password. The file is encrypted with AES-256, the standard in current PDF readers, and you can also set permissions such as no printing or no copying, with a separate owner password. Encryption happens in your browser: neither the document nor the password is sent anywhere. Before the download is offered, the protected file is opened again to check that it needs the password, that your password works and that every page is unchanged.
Processed on your device. Your files are not uploaded.
The password to open encrypts the whole document: without it, the content cannot be read. Permissions (printing, copying, editing) are different: they are instructions to PDF readers, which most follow but some ignore, so they do not reliably stop copying or changes. PDF-OP cannot recover a forgotten password.
or drop a PDF file here.
Encrypting…
How to use Protect PDF
- Select a PDF file or drag it into the box. If it is already protected, enter its current password.
- Type the password needed to open the PDF twice, or let a strong one be generated.
- Optionally set an owner password and choose what people may do: print, copy, edit, comment, fill in forms.
- Keep AES-256 unless the PDF must open in very old readers, select "Protect PDF", note your password and download the protected file. Your original file is not changed.
Good to know: limitations
- Permissions are honoured by most PDF readers but are not a strong protection against copying, printing or editing.
- Digitally signed PDFs: encrypting saves the file again, which makes existing digital signatures invalid.
- An already protected PDF needs its current password first; its protection is then replaced.
- A forgotten password cannot be recovered.
- Very large PDFs may exceed the memory available on phones.
Frequently asked questions
How secure is the protection?
The password to open encrypts every page, image and attachment with AES-256 (PDF security revision 6), the strongest encryption in the PDF standard. How safe the file is depends on the password: a long, random password cannot be guessed in practice, a short or common one can.
What is the difference between the password to open and the owner password?
The password to open is needed to see the document at all. The owner password only controls the permissions (printing, copying, editing) and lets its holder change or remove them in PDF software that respects them. It does not replace the password to open. If you leave it empty, a random owner password is used that nobody knows, so the permissions cannot be lifted later with an owner password.
Do permissions stop people from copying or printing?
Not reliably. Permissions are rules that PDF readers are asked to follow. Adobe Acrobat, Chrome, Firefox and most others do, but some programs ignore them, and anyone who can open the file can print it to a new PDF or take screenshots. Use them as a clear statement of what is allowed, not as security.
Which readers can open the protected PDF?
With AES-256: Adobe Acrobat and Reader 9 or later, Chrome, Edge, Firefox, Safari and macOS Preview, and current apps on phones. Choose AES-128 only if the file must open in Acrobat 7 or 8 or similarly old software; the password is then limited to 32 characters without accents. The older RC4 encryption is not offered because it is broken.
Can you recover my password if I forget it?
No. The password is never sent to us or stored anywhere, so nobody can recover it. Keep your original, unprotected file, and save the password in a password manager.
Are my file and password uploaded?
No. Encryption runs in your browser on your device. The PDF and the password stay there; they are not sent to our servers, not stored and not logged.
Is it free?
Yes. There is no sign-up, no watermark and no daily limit. The site is financed by advertising.