How to password protect a PDF, and when it is enough
Emailing a payslip, a signed contract or a scan of your passport is routine, and so is that email sitting in someone's inbox for years. A password turns the PDF into an encrypted file that only someone with the password can open. Here is how to do it well.
Last updated November 2, 2026 · 4 min read
Two kinds of password
The open password is the one readers must type to view the document at all. This is the one that protects confidential content.
The owner password controls permissions: whether a reader may print, copy text or edit. It does not stop anyone from reading, and a reader who knows it gets full control. Use it to discourage casual copying, not to keep secrets.
Protect a file in your browser
- Open the Protect PDF tool and add the document. It never leaves your device; the encryption runs locally.
- Enter an open password. Use at least 12 characters with a mix of words and numbers; a short password can be guessed by a computer in seconds.
- Optionally set an owner password and untick printing, copying or editing.
- Click Protect PDF and download. The file is encrypted with AES-256, the same standard banks and governments use.
Share the password safely
- Never put the password in the same email as the file. Send it through a different channel, such as a text message or a phone call.
- Avoid obvious choices like the recipient's name, the date or the word password.
- If you send protected files regularly, agree on a password once in person and reuse it only with that recipient.
What encryption does not do
Once a document is open, the reader can take a screenshot, print it to another PDF or photograph the screen. Permissions and passwords protect the file in transit and at rest, not the information after it has been shown. For truly sensitive material, share as little as possible and only with people you trust.
If you later need the file without the password, the Unlock PDF tool removes it, provided you know the password.