How to use Protect PDF
- 1
Choose the PDF you want to lock.
- 2
Type a password and type it again to confirm. Tick "Show passwords" to check for typos.
- 3
Optionally open "Permissions" to block printing or copying, and set a separate permissions password.
- 4
Press "Protect PDF", download the encrypted copy, and test that it opens with your password.
What this tool does
Protect PDF adds an open password to a PDF and encrypts its contents with AES-256. Without the password the file shows nothing, not even its pages. It's useful before emailing bank statements, sharing HR documents, or storing scans of passports in a cloud folder.
Features
- AES-256 encryption (the PDF 2.0 standard handler), not the outdated RC4 used by some older tools.
- Password confirmation and a show-password switch to avoid locking yourself out with a typo.
- Optional permissions: block printing and copying text or images.
- Separate permissions password if you want to be able to change the restrictions later.
Limits
- A PDF that already has a password must be unlocked first.
- Passwords can be up to 127 characters.
- Digital signatures in the original become invalid, because the file is rewritten when it's encrypted.
- Very old readers (from before about 2010) may not open AES-256 files.
Where your file is processed
This tool works in your browser: your PDF is processed on your own device, so it isn't sent to our server for this tool. Some other tools on UtiloNest do use our server, and their pages say so.
Frequently asked questions
How strong is the protection?
The PDF is encrypted with AES-256, the strongest method in the PDF standard, supported by Adobe Acrobat, browsers' PDF viewers, macOS Preview and other current readers. The real strength comes from your password, so use a long one that isn't used elsewhere.
What if I forget the password?
It can't be recovered, by us or anyone else, because we never see it. Keep the unprotected original, or store the password in a password manager.
What is the permissions password?
PDFs can have a second, "owner" password that controls permissions such as printing and copying. Readers ask for the open password; the permissions password is only needed to change those restrictions later. If you restrict something and leave it empty, a random one is used.
Do the print and copy restrictions really stop people?
Mainstream readers respect them, which is enough to discourage casual copying. They are not a hard barrier, though; someone who has the open password can use software that ignores them. Only the open password keeps the content secret.
Where is my file processed?
In your browser. This tool works on your own device, so the file isn't sent to our server for it.