Lock & Protect PDF

Protect PDF secures a PDF with a password using real encryption, so only people with the password can open it, the straightforward way to keep a confidential document private before sharing or storing it.

Because it's genuine encryption, the protection is meaningful, and its strength comes down to your password: a long, unique one is far harder to crack than something short or common. Critically for a security tool, the encryption is applied entirely in your browser, so your sensitive file is never uploaded, uploading a document just to protect it would undermine the whole point.

The flip side of real encryption is that there's no backdoor: lose the password and the file can't be opened. So store it safely and always keep an unprotected master copy before you protect and distribute. And remember protection governs access, not what an authorised holder does next, only share the password with people you trust.

For finer control, restricting printing, editing, or copying alongside the open password, use Lock PDF; to reopen a protected file you have the password for, use Unlock PDF. Everything runs in your browser with no watermark or limit.