Main

I attempt to simplify and shorten the text, and refine the threat analysis by:

• clarifying the separation between the provider of a communication service and the application software and its maker. This allows this analysis to be applicable to cases where the provider of a proprietary service is the maker of its app client, and cases where third-party apps for such a service exist, as well as the case of an open network and open independently-made clients (in which case the questions about the provider are voided)
• expanding the prose on servers, if any, and on trusting them.