Add a Password to a PDF
Encrypt a PDF with a password so it can't be opened without it. Uses real AES-256 encryption, applied entirely in your browser.
Drop a PDF here, or click to browse
Processed in your browser — nothing is uploaded
About this tool
This tool encrypts your PDF using AES-256 — the PDF 2.0 standard encryption method, the same one used by Adobe Acrobat — so the file genuinely cannot be opened without the password you set, not just cosmetically locked. The encryption happens using your browser's built-in Web Crypto API, and your file and chosen password are never uploaded anywhere.
By default, printing is allowed at full resolution, while copying, editing, and other modifications are restricted — reasonable defaults for sharing a document you want people to be able to read and print, but not alter or extract content from.
This is commonly used before emailing a sensitive document, sharing financial or personal records, or protecting a contract or report from being edited by anyone it's forwarded to.
Frequently asked questions
- What encryption does this use?
- AES-256, the PDF 2.0 standard (ISO 32000-2 revision 6) — the same encryption strength used by Adobe Acrobat's password protection.
- Can the password be recovered if I forget it?
- No — that's the point of real encryption. If you lose the password, the PDF cannot be opened by this tool, by Adobe Acrobat, or by anyone else. Store it somewhere safe.
- Is my PDF or password uploaded anywhere?
- No. Encryption happens entirely in your browser using the Web Crypto API — neither the file nor the password ever leaves your device.
- Can I remove the password later?
- Yes, using the Unlock PDF tool, as long as you still know the password.