PDF Files Security app.

I am seeking a smart coder who can design a security software utility application that can prevent PDF files from being stolen , pirated and shared. Example scenario: A person has owns a PDF ebook that he has written, and he is selling the ebook online. Once a customer buys and downloads his ebook, that original purchaser, can now send that PDF files (ebook)to any other person. That person can the open that PDF, read the content, and then continue to distribute it to anyone else, This means that the original author of the PDF ebook is having his book stolen and used freely by others. I realize there are the options within PDF creators where you can set 'security' to prevent copying text, highlighting text etc. But that is basic and does not offer the security I want developed Some programmers have also said that PDF files cannot be secured in the way that I want, because any security that might be embedded into a PDF doc. will be ineffectual if a person were to save the PDF to a different file name than it was originally downloaded as. I have also had a number of programmers who claim to be able to develop such a security utility, but have failed at it miserably. How good are you?