You want to know about the Internet of Things? Quite simply, privacy and secrecy will ultimately be doomed, as they only have to be lucky once. Transceiver equipment is getting so small and compact that soon they'll be able to hide them anywhere: even inside a person or within a necessary piece of lead or other x-ray-beating stuff. Think a device embedded in a skull under the guise of (and employing as an antenna) a metal plate planted under the alibi of a skiing accident or something. They can act passively and only spill their contents on coded signal so they can't be otherwise detected under normal use.