送交者: steven 于 2005-8-13, 19:34:32:
回答: 这当然关系到速度。 由 bluesea 于 2005-8-13, 13:53:16:
system. Typical internet traffic are not time critical, even vedio stream i not time critical. Between two ip endpoints, there are many routers, gateways, firewall, even satellites, however, time isn't a function here. A real-time system say, a beer bottling system, when the sensor senses the bottle is in position, it tells the processor to turn on the valve and fill the bottle with bear, and three seconds later, the valve has to be shutted. This is a real-time system, 3 second is not fast at all, however, the next event has to happen at a 3 second interval, cannot be late, or early. Internet traffic doesn't have this constrain, at worse you will see some delay, but that is okay. Unless you have an application protocol requires you to receive ack within 3 second otherwise drop the connection, and that is a problem, but even without filtering, you will still have problem running this on the internet. Internet protocol doesn't ensure "timely" delivery, never.
Even vedio conference, that is not a problem, since nothing happens instantly, and that is not part of the requirement. I am currently working on implementing a long range wireless network, and we use vedio conference software running on XP as one demo. We see delays, however, the vedio conference is still very smooth, since the delay is pretty much constant. Unless the delay itself is a function of time, there will be no problem.
Besides, you haven't answer the question how you can break a 128bit key cipher text encrypted using one-time pad, or, say just 2 bit key, and see if you can break it.