how can I unlock my PDF without password?

[Janhardin21]

I have a PDF file that I protected with a password some time ago, but now I’ve forgotten the password and can't access its contents. Most free tools I found either require the password or only remove restrictions like editing or printing. I need a way to unlock the PDF entirely without knowing the password.

[nick8606]

Password is transformed to encryption key. Old files use 40-bit key, it can be found during reasonable time. If your file uses 40-bit key then you have good chances to decrypt data without exact password. Newer files use 128 or 256-bit key and require correct password.

Some utilities can remove restrictions and enable locked features. It doesn't mean access to encrypted content.