Protect PDF with a Password
Lock a PDF so only people with the password can open it. Files are encrypted with AES-256 in your browser, and you can also restrict printing, copying and editing. Nothing is uploaded.
Results appear here. Files are processed on your device and never uploaded.
How it works
- Add PDFsDrop one or more files; they are processed on your device.
- Choose a passwordType it twice. Use a long passphrase you can share safely with the recipient.
- Set permissionsDecide whether readers may print, copy text or edit. An owner password (optional) protects these settings.
- DownloadThe encrypted PDF opens in every standard reader after the password is entered.
How strong is the protection?
Files are encrypted with AES-256, the strongest method in the PDF standard (PDF 2.0, revision 6), supported by Adobe Acrobat and Reader, Apple Preview, Chrome, Edge, Firefox and other current readers. With AES-256 the weak point is the password itself: a short or common password can be guessed by software that tries millions of combinations. Twelve or more characters, or four random words, make guessing impractical. Choose AES-128 only if the recipient uses very old software.
Never send the password in the same email as the file. Share it by phone, text message or a password manager, so that someone who intercepts one does not get both.
Open password versus permissions
The password you type is the open password: without it, nobody can see the content. Permissions (printing, copying, editing) are a different kind of setting. Standard readers respect them, but they are enforced by the reader rather than by encryption, and some programs ignore them. Treat them as a polite request that prevents casual copying, not as security. If you leave the owner password empty, a long random one is generated and not shown, so the permissions cannot be changed later without it; keep your original file if you might need to edit it.
Frequently asked questions
Is my PDF uploaded to encrypt it?
No. Encryption runs in your browser using the Web Crypto API. The file and password never leave your device.
I forgot the password. Can you recover it?
No. Nothing is stored, and AES-256 cannot be broken for a good password. Keep your unprotected original somewhere safe.
Can I remove the password later?
Yes, with Unlock PDF, as long as you know the password.
Can I protect a PDF that already has a password?
Unlock it first, then protect it again with the new password.