Protect PDF

The problem with every other free tool for this job

Think about what you are doing when you protect a PDF. The file is a contract, a payslip, a medical letter, a set of accounts, something with an ID number in it. That is why you are locking it.

Now consider that the usual free tools ask you to upload precisely that file to their servers, where it is decrypted-in-the-clear, processed, and stored for some period before deletion. You are handing the sensitive document to a third party in order to make it private. That is the wrong shape for this particular task, however trustworthy the service.

Here the file is read and encrypted in the page. Nothing is transmitted, nothing is stored, and there is no account. Close the tab and there is no trace anywhere but your own download folder.

Change the password before you convert

The password fields start with a placeholder filled in. Replace it. A PDF locked with a value that was sitting in the box is not locked in any meaningful sense.

The tool accepts anything from four characters, but that is a technical floor rather than a recommendation. For anything that genuinely matters, use a long random password from a generator and store it somewhere you will still have it later — which brings us to the part people learn the hard way.

There is no way to recover the password

That is the point of encryption, and it applies to you as much as to anyone else. If you lose the password, the document is not recoverable — not by us, not by any service, not by support. AES-256 has no back door and no reset link.

So before you send a protected file to anyone, check two things: that you have the password saved somewhere permanent, and that the recipient has a way to receive it. Sending the password in the same email as the document defeats the exercise entirely; use a different channel.

Permissions are not the same as the password

The checkboxes for printing, copying text, editing and comments are worth understanding properly, because they promise less than they appear to.

The password is real security: without it the file's contents cannot be read at all. The permissions are flags stored inside the PDF that ask reader software to behave a certain way. Most well-behaved readers honour them — Acrobat will grey out the print button if you turn printing off. Others ignore them, and software exists specifically to strip them.

So use permissions as a clear signal of intent to a cooperative reader — "this is not for editing" — and never as a guarantee. If someone must not be able to copy the text, permissions will not achieve that. Editing is off by default here; printing, copying and comments are on.

Related tools

Password Generator creates a strong random password and shows you its strength in bits, which is the right way to choose one for this. Merge PDF combines documents before you lock the result, and Compress PDF reduces the size first — encrypt last, since a protected file cannot be processed further.