PDF password vs restrictions: why it won't open, print or copy

The two locks side by side

A PDF can carry two separate kinds of lock, and many people meet both without knowing there is a difference. One is a password you type before you can see anything. The other is a set of limits on what you may do with a file that opens fine. Here they are next to each other:

Some files have both: a password to open them, with limits on top. Unlock PDF removes everything in one go. What to do in each case comes further down.

Why some PDFs ask for a password to open

A password to open keeps a file private on its journey. The sender locks it so that only the person it was meant for can read it. Without the password the file can't be read at all, because its text and pictures are scrambled with a key that only the password unlocks.

That is why you meet this lock in files full of personal details: bank and card statements, salary slips, e-Aadhaar, insurance papers and bills.

For the sender the lock is cheap and useful. A statement sent by email may sit in an inbox, on a shared computer or in a cloud folder, and still be unreadable to anyone who finds it. You often don't choose the password yourself. It is often a rule built from details the sender already holds about you, which is why the email that came with the file usually explains it.

How strong is it? As strong as the password. A modern lock such as AES 256-bit can't be broken by trying keys. But a short password, or one made from a name and a date of birth, can be found by someone who knows those details or tries them all. The password is the weak spot, not the lock.

If you know the password and the lock simply gets in your way, removing the password from a bank statement walks through it step by step.

Why others open freely but won't print or copy

The second lock is a different idea. The file opens for everyone, but the person who made it has asked PDF apps to hold some actions back. The request is stored inside the file, together with a second password, the owner password, which only the maker is meant to know. An app that respects the request greys out the button or refuses the action.

Makers use it to discourage casual copying and editing: a form that should be filled in but not changed, an e-book or a paid report that shouldn't be passed around, an official document that shouldn't be edited. The things a file can ask apps to block are these, in the words Unlock PDF uses when it tells you what it removed:

Printing

The Print button is greyed out, or does nothing.

Printing at full quality

Printing is allowed, but apps that respect the block may print only a lower-quality version of the page.

Copying text and pictures

Words can't be selected and copied, and pictures can't be taken out.

Changes

The file can't be edited.

Comments

You can't add notes or highlights.

Filling in forms

The form's fields won't take your answers.

Adding, removing or turning pages

Pages can't be added, taken out or rotated.

A file can block any mix of these, and allow the rest.

Restrictions are a request, not a lock. Nothing is scrambled, so anyone who can open the file can read all of it. Apps that respect the request obey it. Apps that don't respect it ignore it, and so do tools that remove it, including Unlock PDF. A screenshot or a photo of the screen gets around it too. So restrictions stop casual copying by honest people. They don't stop a person who is determined.

How to tell which lock your PDF has

Open the file in any PDF app or browser, and watch what happens first:

Before you blame the lock

• A scan can't be copied from. A scanned page is a picture, so there is no text to select, with or without a lock. If Unlock PDF says the file is "Not locked" and you still can't select a single word, the pages are almost certainly pictures. Unlocking won't change that.
• The block may be in the app. A greyed-out Print button can come from the PDF app rather than the file. Try opening the file in a different app or browser.

Let the tool check for you

The quickest test is to add the file to Unlock PDF. It checks the lock as soon as the file is added, and the row tells you what it found:

• A file that needs a password shows a lock and a password box.
• A file with restrictions only is unlocked straight away, and the row says what was blocked.
• A file with no lock says "Not locked", so you know to look elsewhere, at the app or at a scan.

Nothing is uploaded while it checks. Your file stays in your browser.

What to do in each case

A password to open, and you have it

Add the file to Unlock PDF, type the password and press Unlock. Then press Download. The copy opens without a password and has nothing blocked. If the file has both locks, either password will do: the one you were given, or the owner password if you have that.

A password to open, and you don't have it

Unlock PDF can't help here. It never guesses passwords and never tries to break a lock, and a file with a modern lock and a good password can't be opened without its password by anyone. Often the password isn't lost, though, only unread: the email the file came with, the sender's website or app, or their customer care or your HR team can usually tell you how it is made. Finding a statement's password goes through each place, with a worked example of turning a rule into a password.

Stay away from sites that offer to "recover" the password. To try, they need your file, and then your private document sits on someone else's computer. The Unlock PDF guide has more on this.

Restrictions only

This is the easy case. Add the file and type nothing. A file that only restricts printing or copying is unlocked at once, and the row says "It needed no password: it only had restrictions." It also lists what it removed, in words like "printing" and "copying text and pictures". Press Download, then print or copy from the new file.

It is quick. In our tests, a 117-page maths textbook with only printing, copying and changes blocked (AES 256-bit, no password to open) went from 5.09 MB to 5.03 MB in 0.6 s, timed from adding the file. We ran it in Chromium 141 on a Linux computer with 4 processor cores and 16 GB of memory, after locking it with qpdf, a widely used PDF program. The time is the middle of three tries, and your device may be faster or slower.

Both locks

If you have either password, Unlock PDF takes both locks off in one go. If you have neither, you are back at "a password to open, and you don't have it". The owner password lifts the blocks and also opens the file, but it is meant for the maker, so you will rarely have it.

No lock at all

If the row says "Not locked", the file has no password and no restrictions, so there is nothing to remove. Look at the app, try another one, or check whether the file is a scan.

A certificate or reader plug-in lock

A few PDFs are locked with a digital certificate, or for a special reader app, instead of a password. There is no password to type, so Unlock PDF says it is locked in a way it can't open. Only the app or the person the file was made for can open it. Ask the sender for an ordinary copy.

What the unlocked copy is like

Unlocking takes the lock off every part of the file and writes it out again. Nothing on the pages is redrawn, so the copy looks and works like the original did once it was open:

• Pages, text and pictures stay the same, in the same order. Text stays searchable and copyable.
• Links and bookmarks still work. In our tests the textbook above kept all 35 of its bookmarks and 509 links.
• Forms keep their fields and anything already filled in. A filled-in one-page application form kept all 8 of its answers.
• The size stays about the same, often a little smaller. The copy's name ends in -unlocked, and your original stays as it was.

Two things change on purpose, and one changes as a result. The copy has no password and nothing in it is blocked. And a digital signature, the coded seal that shows a file hasn't changed since it was signed, is no longer valid on the unlocked copy. The row tells you when that happens. Keep the original if an office needs to check the signature.

Unlocking also doesn't turn a scan into text: a scan stays a scan, so its words still can't be searched or copied. And remember what you now hold. A copy with no limits can be printed, copied and passed on by anyone who gets it, so keep it as carefully as you would keep the paper original. The guide lists everything that stays the same.

Is it all right to lift a lock?

For your own documents, and files you are allowed to use, removing a password you were given is much like opening the file and saving a copy. Restrictions are a little different, because they show what the maker wanted. Here is a fair way to think about it:

• Usually fine. A form you have to fill in and print. A statement or certificate that is yours. A file a colleague or a client sent you to work with.
• Ask first. A book, a paid report, course material or anything else whose maker locked it to protect their work. Removing the restriction doesn't change who owns the work or what you may do with it. If you are unsure, ask the sender.
• Not possible. A private file you have no password for. Unlock PDF needs the password, so it can't be used to get into someone else's statement.

If you are the one adding a lock

If you send files to others, knowing the difference helps you pick the right lock:

• To keep a file private, use a password to open. Make it long and hard to guess, not a name and a birth date. Protect PDF locks a copy of your file with AES 256-bit.
• To discourage printing or copying, add restrictions. Protect PDF has an option to block printing, copying or changes, with an owner password of your own. People who know only the password to open can read the file, but they get the restrictions. The guide explains it.
• Treat restrictions as a polite request. They hide nothing. To keep something from a person, don't give them the password to open.
• Remember the password. If it is forgotten, nobody can open the protected copy: not you, not us, not anyone. Keep your original file too.

Changing a password instead of removing it

Sometimes you don't want the lock gone, only a different one. Say you need to forward a statement to a family member, but you don't want to share the password made from your own details. You don't have to unlock it first. Add the locked file to Protect PDF, type its current password in the box on its row, then choose the new password, and blocks if you want them. The old lock is taken off and replaced with the new AES 256-bit lock, and the row says which lock was replaced. To only remove a password, with no new one, Unlock PDF is the tool.

Questions people ask next

Is the owner password the same as the password to open?

No. They are two passwords with two jobs. The password to open is needed to see the file at all. The owner password lifts the blocks on printing, copying and changes, and it also opens the file. Either one unlocks a file in Unlock PDF.

Can Unlock PDF remove a password I don't know?

No. The only files it opens without a password are those that open freely and just block printing, copying or changes. A file that needs a password to open can only be unlocked with that password or its owner password.

If printing is blocked, can people still read the file?

Yes. Restrictions don't hide anything. Only a password to open keeps people out.

Why do banks use passwords while forms use restrictions?

They usually want different things. A bank wants the statement private, so it uses a password to open. The maker of a form often wants it read, filled in and printed by anyone, but not changed, so restrictions are enough.

Does unlocking lower the quality?

No. Nothing on the pages is redrawn or compressed again.

Can I do this on my phone?

Yes. Open Unlock PDF in Chrome on Android, or in Safari on iPhone and iPad. There is no app to install. The steps are in the article on bank statements.

Is my file uploaded?

No. The file and any password stay in your browser, on your own device.