What is the difference between user and owner password in a PDF?+
The user password (also called open password) must be entered to open the document. The owner password controls permissions like printing, copying text, and editing. A PDF can have both, or just an owner password with unrestricted opening.
Can I remove a PDF password without knowing it?+
No. Password-protected PDFs use AES-256 encryption. If you don't know the password, there is no legal way to remove it with this tool. You must have the correct password to remove protection.
What encryption strength is used?+
Modern PDFs use AES-256 encryption (PDF 1.7 standard). This is the same encryption standard used in banking and government applications. Passwords under 8 characters are vulnerable to dictionary attacks; use strong, unique passwords.
Does password protection prevent all copying?+
Copy-protection (owner password without user password) can be bypassed by some tools and is not a strong protection. For truly sensitive documents, consider document rights management (DRM) solutions instead.