Password-protect a PDF
A password to open it, and rules for what it may be used for
Choose a password that opens the file, an owner's password that guards what it may be used for, or both. Without the opening password the file is unreadable: it is encrypted with AES-256, the strongest encryption a PDF has, and never with the old 40-bit or 128-bit RC4 some tools still use. With the owner's password you can withhold printing, printing at full quality, copying text and images, editing, annotating, filling in forms and moving pages.
Said plainly: the opening password is what keeps a file private. The permissions are honoured by PDF readers that follow the standard, and a reader that ignores them can still print a file it can open. A screen reader may always read the text aloud; the standard says so, and so does this tool.
Checked before you get it
The protected file is opened again before it is handed back: it must not open without its password, the opening password must give exactly the permissions you chose, the owner's password must give all of them, and decrypted it must be your file, object for object. A file that fails any of that is not returned. Passwords are used once, to protect it, and are never stored or written to any record. A password can be up to 40 characters.
Protect a PDF now — it opens the tool, with nothing to install.
The record
Nothing is stored: the file you send comes back protected or unlocked, and the record of what was done travels inside it. Your account's trail keeps the file's fingerprint, the encryption and the permissions — never a password.