Password protect a PDF
Add a password so the document cannot be opened without it.
Or drop one anywhere on this page
What to know about Protect PDF
Encrypt a document so it cannot be opened without the password, and choose what readers may do once it is open. This matters more than usual here: because encryption runs on your device, neither the file nor the password you choose is ever transmitted to anyone.
The encryption is AES-256, written into the file itself, so the protection travels with the document rather than depending on where it is stored or who is hosting it.
Two things deserve saying plainly. The strength of the result is the strength of the password you pick — a short or guessable one is the weak link, not the cipher. And permissions such as “do not print” or “do not copy” are requests that a reader's software chooses to honour; they are not locks the file can enforce, and any tool claiming otherwise is overselling what the PDF format can do.
A password-protection service that receives both your document and your password is a strange thing to trust with either. Doing it in the browser removes the question.
How to password protect a PDF
- 1
Choose the PDF
Drop in the document you want to encrypt.
- 2
Set a password
Enter and confirm the password. Its strength is assessed on your device as you type.
- 3
Download the protected file
The encrypted PDF is saved to your device and will ask for the password when opened.
What Protect PDF accepts and produces
- Input
- One PDF, and the password you choose.
- Output
- The same document encrypted with AES-256, which a reader must have the password to open.
- Limits
- Encryption is only as strong as the password: a short or guessable one is the weak link, not the cipher. Permissions such as printing are enforced by the reader, not by the file, so a determined viewer can ignore them.
- Offline
- Yes, once the encryption engine has been fetched on your first visit.
Why Protect PDF here
- AES-256 encryption applied locally in your browser
- The password is never transmitted or stored anywhere
- Restrict printing, copying, editing and form filling
- Works with your internet disconnected
Where your file goes
Nowhere. This tool runs inside your browser, and the page is served with a policy that forbids it from sending your document anywhere. You can confirm that yourself: open your browser’s developer tools, watch the Network tab, and process a file.
Questions
Is my password sent to TryToPDF?
No, and it cannot be. Encryption happens inside your browser, and the tool page is configured so it cannot make network requests during processing. The password exists only in your device's memory while the file is being encrypted.
What happens if I forget the password?
The document cannot be opened. There is no recovery, no backdoor and no reset — that is what makes the encryption meaningful. Store the password somewhere safe before you send the file on.
How strong is the encryption?
AES-256 where the document format allows it. The real limit on security is the strength of your password, so choose a long one rather than a short complicated one.
What is the difference between the password and the permissions?
The password decides who can open the document at all, and is enforced by encryption. Permissions decide what someone who has already opened it may do — print, copy text, edit, fill forms. They are two separate controls and you can use either or both.
Can I stop people printing or copying my PDF?
You can ask them not to. PDF permissions are advisory: they are recorded in the document and honoured by mainstream readers such as Acrobat and Preview, but the PDF format has no way to enforce them, and software that ignores them exists. Treat permissions as a clear statement of intent, not as a security control. If a document must not be read by someone, use a password.
What is the difference between the two passwords?
The one you set first is required to open the document at all, and is enforced by encryption. The optional owner password is what makes the permission restrictions mean anything — without it, anyone who opens the file holds owner rights and can ignore them.
Can I remove the password later?
Yes, with Unlock PDF, as long as you have the password. Removing protection needs the password just as opening it does.
Will the protected file open on a phone or tablet?
Yes. AES-256 is the standard modern PDF encryption and every current reader supports it, on desktop and mobile alike.
Does encrypting change the document?
No. Pages, text, images, forms and annotations are all preserved exactly. Only the way the file is stored changes.
Worth reading about Protect PDF
- Preparing a scanned document to sendA scan hides text you cannot see and metadata you did not add. What to check, and in what order, before a scanned document leaves your hands.
- Sending several documents at onceMerging, zipping and splitting solve different problems. Which one to reach for when you have several files to send and a size limit you have to meet.
- Are online PDF tools safe?Most PDF sites upload your document to a server. Four checks that tell you what a tool really does with your file, without taking anyone's word for it.
- PDF work for HR teamsHiring and personnel paperwork is dense with personal data. How to bundle, redact and share it without creating a data-protection problem for yourself.