well sorry for the ambiguity, i was deep in thought as i typed it which i often do when this tired.... and on these painkillers i got for my foot, it is similar to being stoned now i think about it... but either way..
my real question was 2 things.. 1, what's the max theoritcal speed of USB transfrer. 2. would it be succesfull a basic enough prototype to convince someone to one day mass market with rollable key codes with more encrpytion and more layers... but right now i'd be curious how to write some kind of hyperterminal application and talk to someone all encrpyted via a simple server pc > arduino > pc > router > adsl/etc > server > arduino > server > process it, and so on, could even be added into an existing modem/router to encrpyt the packet with a value (which please don't worry about...) and once again send it back....
but how long before your ISP works it out and decodes it, you move onto a better encryption routine and a new C++ file comes out to stop it... some may say you could use it to cover piracy eg torrent downloading illegal movies... but i say, fine you get to know my mac address and you get to know where i'm visiting ip the website you visit, but then the data you download can not be seen by anyone but you, now why this method of say ssl, a secure connection https? well if your ISP is watching then surely they can see the data you both send and receive, so all it would mean is to replay that exact same sequence of events and you get to see everything would you not? (Could be wrong but if you have all the packets sent/recv from both ends all of it, then you could simply modify the header to point to a new server..
but anyway side tracked, more secure a way they can't track the data because it's encrypted unless they too have an arduino and share the code would it lead to someone cracking it to prevent us doing this? what's your opinion and fastest speed i could get over serial.