Protect PDF
Add a password to prevent unauthorised access
Drop a PDF here or click to select
Single PDF file
Password protect PDF files online for free
OPUS PDF Protector adds a strong password to any PDF file instantly — no software, no signup. Whether you're securing a contract, a confidential report, or sensitive personal documents, our free online tool encrypts your PDF with AES-256 encryption in seconds.
How does PDF password protection work?
Upload your PDF, set a password, and our server applies AES-256 encryption — the same standard used by banks and governments. The protected PDF can only be opened by someone who knows the password. We never see or store your password; encryption happens server-side and the key is never logged.
Your files stay private
Your PDF and password are used solely for the encryption process and deleted immediately after your protected file is ready. We do not store, log, or have access to your documents or your chosen password at any point.