Protect PDF

Password-protect a PDF with AES-256 encryption and choose whether people can print, copy, edit, comment, fill forms or move pages.

Reviewed by Dany, RightSums team · Updated

Runs in your browser. Your files are not uploaded.

pdf-security · PDF tool · UK & US

Type a password to open the file, confirm it, and a strength meter shows roughly how hard it is to guess. The PDF is then encrypted with AES-256, the strongest encryption in the PDF standard, so it cannot be opened without that password. You can also decide what people may do once it is open: print, copy text and images, edit content, add comments, fill in forms, or insert, rotate and delete pages. Readers such as Acrobat, Preview and browsers respect these permissions, but they are not a hard barrier. Set a separate owner password to change them later; otherwise a random one is used. The password never leaves your device and cannot be recovered if forgotten.

Accepted inputs

  • PDF

Outputs

  • Encrypted PDF (AES-256)

How to use the Protect PDF

  1. Drop your PDF into the box, entering its current password if it already has one.
  2. Type the password needed to open the file and type it again to confirm.
  3. Tick what people may do after opening it, and add a separate owner password if you want one.
  4. Click Protect PDF and download the encrypted copy.

Frequently asked questions

How do I password-protect a PDF for free?

Load the PDF, type a password twice and click Protect PDF. The downloaded copy is encrypted with AES-256 and asks for the password every time it is opened, in any standard PDF reader.

How strong is the encryption?

Files are encrypted with AES-256, the strongest method in the PDF specification and supported by all modern readers. The real weak point is the password, so use 12 or more characters, or a passphrase of several random words.

What if I forget the password?

It cannot be recovered. The password is never sent to or stored by us, and there is no reset option, so keep it in a password manager and keep an unprotected copy of the file somewhere safe.

Can I stop people printing or copying my PDF?

Yes. Untick Print or Copy text and images before protecting the file. Standard readers honour these permissions, but some software ignores them, so treat them as a deterrent rather than a guarantee.

What is an owner password?

It is a second password that controls the permissions rather than opening the file. If you do not set one, a random owner password is created, which means the permissions cannot be changed later without your original unprotected file.

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