Protecting a PDF with a password
Email attachments get forwarded, cloud links get shared and laptops get lost. A password on a PDF means that only people who know it can open the document, wherever the file ends up. It is a sensible step for payslips, tax forms, contracts, medical letters and anything containing personal data.
How the encryption works
The file is encrypted with AES-256, the strongest standard encryption defined for PDF and supported by Adobe Acrobat, Preview, Chrome, Edge and other modern readers. The document cannot be opened without the password; the encrypted contents are not readable by opening the file in another program.
Encryption happens in your browser. The password and the document are never sent to a server, which also means the password cannot be recovered for you if it is lost.
Choosing a strong password
The tool accepts passwords of four characters or more, but strength comes from length. A passphrase of three or four unrelated words is both stronger and easier to remember than a short mix of symbols. Avoid names, birthdays and reused passwords.
Sharing protected files
Send the password through a different channel from the file — for example, email the PDF and share the password by phone or text message. If both travel in the same email, anyone who gets the email can open the document.
Tips for protected PDFs
- Store the password in a password manager.
- Protect the final version — make edits, merges and compression first.
- Add a watermark as well if you want to show the document is confidential once opened.