Password-Protect a PDF: When and How

Modern PDFs encrypt with AES-256 (older ones used weaker RC4 — broken). The password protects against opening or against editing/printing. The "owner password" allows changes; the "user password" allows opening. Common mistake: setting a 4-character password thinking it is secure. Use 16+ random characters from our Password Generator. Note: if you forget the password, the file is unrecoverable through legitimate means. Our PDF Protect tool encrypts; PDF Password Remover unlocks PDFs you have the password to.