Protect PDF with a Password
Password-protect a PDF with AES-256 encryption in your browser. Optionally restrict printing, editing and copying — free, private, no uploads.
🔒 Runs entirely in your browser — nothing is uploadedAdd a password to a PDF privately
Bank statements, contracts, medical records and HR documents often need to travel by email or through shared folders. Adding a password means only people who know it can open the file, even if the attachment is forwarded or a link leaks. This tool password-protects a PDF using AES-256 encryption, the strongest scheme defined in the PDF 2.0 standard and supported by Adobe Acrobat, Preview, Chrome, Edge, Firefox and all modern readers.
Uploading a confidential document to a website just to lock it defeats the purpose. Here the work is done by qpdf, a respected open-source PDF toolkit compiled to WebAssembly and running inside your browser tab. The file, the password and the encrypted result all stay on your device.
Open password, owner password and permissions
PDF encryption uses two passwords. The open password (also called the user password) is required to view the document at all. The owner password governs permissions: whether the reader may print, edit or copy text. By default all actions are allowed and the owner password is the same as the open password. If you untick any permission and leave the owner field empty, the tool generates a long random owner password so nobody — including you — can remove the restrictions with the open password alone. Keep in mind that permission flags are honored by well-behaved PDF readers but are not as strong as the open password itself; the encryption is what truly protects the content.
Choosing a good password
AES-256 is effectively impossible to break directly, so attackers try to guess the password instead. Use at least 12 characters, ideally a passphrase of several unrelated words, and never reuse a password from another account. Share the password through a different channel than the file — for example, send the PDF by email and the password by text message. There is no way to recover a forgotten password, so store it in a password manager. If you later need an unprotected copy, use the Unlock PDF tool together with the password.
How to use
- Choose a PDFDrop the PDF you want to protect or click to browse.
- Set a passwordType and confirm the password, and optionally restrict printing, editing or copying.
- DownloadClick Protect & download to save the encrypted copy.