PDF Protect
Add a password to a PDF to restrict who can open or edit it. Runs entirely in your browser — your file is never uploaded.
What is PDF Password Protection?
PDF password protection adds a password to a PDF file that must be entered before the document can be opened or edited. The PDF standard supports two types of passwords: a user password (required to open the document) and an owner password (required to change permissions such as printing or copying).
This tool adds AES-256 encryption to a PDF entirely in your browser — your file is never uploaded.
How to password-protect a PDF online
- Upload your PDF file.
- Enter the password you want to set.
- Click Protect and download the encrypted PDF.
Frequently Asked Questions
What encryption algorithm is used?
This tool uses AES-256, the strongest encryption level supported by the PDF specification. AES-256 is the same standard used by government and military organisations worldwide.
What is the difference between a user password and an owner password?
A user password is required to open the PDF. An owner password is required to change permissions (printing, copying, editing). This tool sets a user password.
Can a protected PDF be unlocked without the password?
AES-256 encrypted PDFs cannot be brute-forced with current technology. However, older PDF encryption such as 40-bit RC4 can be broken easily. Always use the strongest available encryption.
Is my PDF secure during this process?
Yes. All encryption runs in your browser using the Web Crypto API. Your PDF is never sent to any server.