PDF Password Protector

This free online PDF password protector locks a PDF with real AES-256 encryption — the same standard Adobe Acrobat's own password protection uses — so only someone with the correct password can open it. Type a password, confirm it, and download an encrypted copy of your file; anyone without that password sees nothing but an unreadable, locked document when they try to open it in any standards-compliant PDF reader.

It goes beyond a simple "require a password" tool, though, because opening a document and doing whatever you want with it are two different problems. A second, independent set of controls lets you restrict printing, copying text, and editing — even for someone who does have the password to open the file. That makes it possible to share a document freely, with no open password at all, while still preventing people from printing it, extracting its text, or altering its content; or to require a password to open it and separately lock down what happens once it's unlocked. Few free browser-based tools expose that distinction at all, and it's often exactly what a contract, a report, or a deliverable actually needs.

A live password strength meter gives immediate feedback as you type, since a locked PDF is only as secure as the password protecting it. Just as importantly, the tool automatically generates a separate, random internal owner key that's never shown to you or stored anywhere — a detail that matters because in the PDF specification, if a document's open password and its permission-owner password are the same value, some readers grant full unrestricted access to anyone who knows that one password, silently defeating any printing or copying restrictions you set. Keeping them distinct is what makes the restrictions actually hold.

Encryption happens entirely inside your browser — the file is never uploaded to a server, which matters most for exactly the kind of documents people password-protect: contracts, financial statements, legal filings, HR records, and anything else that shouldn't be readable by whoever it's sent to next. There's one thing worth knowing going in: the password you set is not recoverable if it's lost, by this tool or anyone else, since the encryption is real — so keep it somewhere safe.