Recently my friend and I were discussing his idea of protecting the digital media that he has been generating.
His initial idea was to encode the data using proprietary encoding algorithm and distribute the media player to the customers separately. My first reaction was, if it's so easy, everyone would have done that. The problem is that this implementation can easily fall prey to chosen plaintext attack.
His later idea was to encrypt the file using a key (say a combination of some metadata of the media file) and then distribute it to the customers. He would use a standard encryption library instead of writing his own implementation. My concern here is that if the decrypting and then rendering the file would slow down the system to be useful for use cases like live streaming.
Is the above approach an efficient way to securely serve content to a limited audience? Also, the sharing method could be live streaming watched on the proprietary software (not a web application).