rishab@dxm.ernet.in (Rishab Aiyer Ghosh) writes:
wcs@anchor.ho.att.com writes:
I'm not sure I really believe it's workable, but what it does sound a bit like is CDMA spread-spectrum, which lets a bunch of
Um no. The main thing is that what is extracted with the selection key is _different_ from what was put in...
Let me get straight where we are. Rishab's concrete proposal was not an implementation, but rather a set of requirements. There was no suggestion about any specific algorithms that would meet those requirements, right? The question is whether any such algorithm could exist. It is hard for me to see how this could possibly work. The message receiver sends this "selection key" to the intermediary, and that somehow pulls out the saved message, but in a form such that the intermediary doesn't recognize it. And the intermediary himself can't tell exactly which message is produced. But it is nevertheless exactly the message which was meant for this particular receiver. The thing is, the receiver does not have much more information than the intermediary. At best he knows a secret key which may help decrypt the message in some way. But I don't see how that can be used to pull out the message data since it can't be revealed to the intermediary. I can't really prove that this is impossible, but it certainly looks that way. Hal