How to pass Password in Password Protected PDF using C#

Here's a project that loads an image then saves it as PDF specifying owner password and user password:
http://support.leadtools.com/CS/forums/42259/ShowPost.aspx
The project uses VB6 but I know leadtools has .NET assemblies for loading and saving secure PDF as well.

As far as I know, you must know the owner password of the encrypted PDF file if you try to decrypt PDF document in C# or remove the password.

regards
alex