How to password-protect a PDF (and remove it later)

You need to email a tax return, a payslip or a scan of your passport. Once it leaves your outbox, it can be forwarded, saved to a shared drive or opened by the wrong person. A password keeps the pages locked wherever the file ends up.

This guide explains the two kinds of PDF password, how to add one for free, how to pick a password that holds up, and how to remove a password you know when you no longer need it.

Open passwords and permission passwords

PDFs support two kinds of password, and they do very different jobs.

An open password (sometimes called a user password) is needed to open the file at all. Without it, the pages are encrypted and nobody can read them.

A permission password (or owner password) lets anyone open the file but limits what they can do with it, such as printing, copying text or editing. Those limits only work if the PDF app respects them. Many apps do, but some don't, and plenty of tools can strip them out. Our own password remover clears print and copy limits from a file that opens freely, without asking for any password.

The short version: if the content is private, you need an open password. Permission limits are a useful extra on top, not a lock.

How to password-protect a PDF for free

Pagestro's Protect PDF tool works in your browser. The file and the password stay on your device and are never uploaded.

Step 1. Open Protect PDF and add your file. You can drop it in or pick it from your computer or phone.

Step 2. Type a password. Pagestro doesn't allow commas in PDF passwords, so pick one without them.

Step 3. Choose the permissions. Printing is blocked by default. You can also block copying text and images, and block editing, comments and form filling. If the person needs to print the file, untick the printing limit.

Step 4. Download the protected copy. Open it once to check that it asks for the password and that the password works.

Pagestro encrypts the file with 256-bit AES, the strongest option in the PDF standard. Current PDF readers on computers, in browsers and on phones can open it.

Two things to know. First, Pagestro always adds an open password, and the permission limits sit on top of it. Second, the permission password is created at random and never shown, so if you want to change the limits later, remove the password and protect the file again.

How to choose a strong password

A locked PDF has no "too many attempts" lockout. Anyone with a copy of the file can keep guessing with software for as long as they like. That makes length the thing that matters most.

The US National Institute of Standards and Technology (NIST) says in its current password guidance that a password used on its own should be at least 15 characters long. The same guidance drops the old rules that force a mix of symbols, numbers and capital letters.

In practice:

• Use a passphrase of four or five random words that only you would put together. Don't use a famous quote or a song line.
• Use a different password for each file or each person you send files to.
• Avoid names, birthdays, phone numbers and account numbers. Anyone who knows you could guess them.
• Save it in a password manager so you can find it later.

How to share the password safely

Never send the password in the same email as the file. If someone gets into that inbox, they get both.

Send the file by email and the password by text message, or read it out on a call. For a client you work with often, agree once on how you'll swap passwords, then stick to it. Don't put the password in the file name or the email subject.

How to remove a password you know

Bank statements and payslips often arrive locked, and typing the password every time gets old. You can save a copy without it.

Step 1. Open Pagestro's password remover and add the locked PDF.

Step 2. Enter the password you use to open it.

Step 3. Download the copy. It opens without a password, and print and copy limits are cleared too.

This also runs in your browser, so the file and the password aren't uploaded. A few things to know:

• Pagestro doesn't crack or guess passwords. If you've lost the password, ask the sender for a new copy.
• Only remove passwords from files you own or have permission to open.
• To change a password, remove the old one first, then add a new one with Protect PDF.

When a password isn't the right tool

A password protects the whole file. But anyone you give the password to can save an open copy and pass it on, and you can't take the file back.

If you need to hide part of a document from the people who will read it, such as an account number on a statement, redact it instead. Our guide to redacting a PDF properly explains how, and Pagestro's Redact PDF tool removes the content rather than just covering it.

If your company has rules for sending personal data, such as a secure portal or encrypted email, follow them. A password-protected PDF is a good everyday step, not a replacement for those systems.

Frequently asked questions

Is a password-protected PDF safe to email?

For most everyday documents, yes, as long as you use an open password that is long and unique and you send it through a different channel. The password is usually the weak point, not the encryption.

Can I password-protect a PDF on my phone?

Yes. Open Protect PDF in your phone's browser, add the file, type a password and download the locked copy. There's no app to install.

What happens if I forget the password?

Pagestro can't recover it, because it never sees it. Keep the original file somewhere safe until you're sure the password is stored.

Can I block printing without adding an open password?

Not with Pagestro, which always adds an open password. Permission-only limits are easy to remove anyway, so don't rely on them for private files.

Does Pagestro see my file or my password?

No. Both stay in your browser on your own device, and nothing is sent to Pagestro.