The reader will open the file, but you can't print it. That's a feature of pdf-files that can be set when making it.
A password protected pdf works different. You need the password to open the file. So this is not a password protected pdf-file. And that's why it opens without the reader asking for a password.
So now back to the supplier (you didn't tell who wrote the program you downloaded, nor the name of the program and ask how to use the password. Unless, of course, a screen print is enough for your purpose.