Add a password to a PDF
Drop a PDF here, or click to browse
This tool uploads your file — it's deleted automatically in 15 minutes
Some documents should not be readable by whoever happens to open the email they arrive in — a salary slip, a bank statement, an ID scan. Adding a password encrypts the file so it cannot be opened at all without it. This uses AES-256, the strongest encryption PDFs support, and you can optionally stop the document being printed. Keep the password safe: there is no recovery, by design.
What a PDF password actually protects
A PDF can carry two different passwords and they do very different jobs. A user password — the one this tool sets — encrypts the content, so the file is unreadable without it. An owner password only records restrictions, such as no printing or no copying, and leaves the document itself readable by anyone; readers choose to honour those restrictions, and plenty of software ignores them. If your aim is that the wrong person cannot read a salary slip, you want the user password, which is what you get by typing one here.
Choosing a password you will still have next month
The most common failure with an encrypted PDF is not an attacker, it is the sender losing the password before the recipient needs it. There is no reset. Before sending, put the password somewhere separate from the file — a password manager, or a message on a different channel from the one carrying the document. Sending both in the same email defeats the point entirely, which is worth saying because it is what most people do.
Why this tool uses a server
Nearly every PDF tool on this site runs in your browser and never uploads anything. This one cannot: the library those tools use has no encryption support whatsoever, and there is no practical way to do AES-256 PDF encryption client-side today. So the document is uploaded, encrypted, and removed within fifteen minutes. If that is not acceptable for a particular file, most desktop PDF readers can set a password locally.
Frequently asked questions
- How strong is the encryption?
- AES-256, which is the strongest option the PDF format offers and is what banks and government departments use. The older RC4 modes some tools still default to are broken and are not offered here.
- What if I forget the password?
- The file cannot be opened. There is no recovery, no backdoor and no record of your password on our side — that is what makes the encryption worth anything. Store it somewhere you trust before you send the file.
- Does blocking printing actually prevent printing?
- It sets a restriction that readers are expected to honour, and mainstream readers do. It is not encryption though, so treat it as a deterrent rather than a guarantee — unlike the password, which genuinely prevents opening the file.
- Can I protect a PDF that already has a password?
- Not directly. Remove the existing password first with the unlock tool, then add the new one. Layering encryption is not something the format supports cleanly.
- Is my file uploaded?
- Yes. pdf-lib, which runs the browser-side PDF tools here, cannot encrypt at all, and no credible client-side alternative exists for AES-256. So this is one of the few tools that genuinely needs a server. The file is deleted automatically within 15 minutes.
- Is the password stored anywhere?
- No. It is used to encrypt the file and then discarded with the request. Nothing about it is logged.
- Will the password work in every reader?
- Yes. AES-256 PDF encryption is supported by Adobe Acrobat, Preview on macOS, Chrome, Edge and every current mobile reader.