Password protect a PDF.
Protecting a PDF encrypts the file with AES and a password of your choice, minimum 3 characters. Only someone who knows the password can open the document afterwards. There is no recovery: it is real encryption, with no back door. It is part of the Premium subscription, 1.99 EUR per month.
Three steps, nothing to install.
The file never leaves your computer during the process.
Choose the file
Drop the PDF into the tool. It stays in your browser the whole time.
Write the password
At least 3 characters. The longer and less obvious it is, the stronger the protection.
Download
The protected PDF is ready to download, already asking for the password when anyone opens it.
What happens if I lose the password?
You lose access to the file. The encryption is real and has no back door: BestPDFInTheWorld does not keep a copy of the password, and there is no way to recover it once the PDF is protected. If you are not sure you will remember it, save it in a password manager before downloading the file.
How strong is the protection? Does the strength come from the algorithm or the password?
Mostly from the password. The algorithm, AES, is a robust cipher used as an industry standard. The weak link is never the algorithm: it is a short, obvious, or reused password. The tool accepts passwords from 3 characters upward, but that is the technical minimum, not a recommendation. A long, unpredictable passphrase protects far more than a short password that is only technically valid.
Is this a free or Premium tool?
Premium. The only free tool on BestPDFInTheWorld is Compress PDF, up to 10 MB and five times a day. Password protect, like the other ten tools, is included in a single subscription of 1.99 EUR per month, with no limits and no annual plan.
Are my files sent to any server when I protect them here?
No. The encryption runs in JavaScript inside your browser: the PDF and the password never leave your computer or pass through a server. This matters in particular for contracts, client data, or documents subject to data protection rules, where sending the file elsewhere would already be a problem before you even reach the result.
More questions about protecting a PDF.
Can I stop whoever opens the PDF from printing it?
Not with this tool. Protection always asks for the password to open the file, but high resolution printing remains permitted to anyone who has it. There is currently no separate option to restrict printing, copying or editing.
Is there a file size limit for protecting a PDF?
No. The 10 MB limit only applies to the free compression tool. Password protect is a Premium tool and does not have that limit.
Do I need to be signed in to use this tool?
Yes. Password protect is not the free tool, so you need to be signed in with an active Premium subscription.
Does it work on mobile?
Yes. You can choose the file, write the password, and download the protected PDF directly in your phone's browser.
Got a document
to protect?
Encrypt it with a password, without leaving the browser. Part of Premium.
Open the protect tool