I remember seeing a list of
Carnivore keywords that an aspiring hax0r type I knew years ago used to embed in the body of his emails. The idea was that, if every email contained references to bomb making, cocaine smuggling and meth lab construction, the volume of data that required human analysis would render the system useless.
With respect to public key encryption...I've never been 100% certain that there are no in built 'back doors' to decrypting messages. According to an IT professor I had in college who specialized in VoIP data security, a lot of the math involved in developing public key encryption was worked on by the NSA and there are chunks of algorithms buried in there that don't seem to do 'anything'. Didn't Microsoft have an issue whereby they built an NSA key into the encryption methods available on a version of Windows a couple of years ago?
Of course, as long as you're doing nothing wrong, why would you be bothered by that
