On Wed, 26 Jun 2002, Donald Eastlake 3rd wrote:
"Privacy", according to the usual definitions, involve controlling the spread of information by persons autorized to have it. Contrast with secrecy which primarily has to do with stopping the spread of information through the actions of those not authorized to have it.
We have thousands of years of experience with military crypto, where the parties at both ends of the conversation are highly motivated to restrict the flow of private information. The current state of this technology is very robust.
That's secrecy technology, not privacy technology.
I have seen "private" and "secret" defined in exactly the opposite fashion as regards keys: a "private" key is private because you never ever share it with anyone, whereas a "secret" (symmetric) key is a secret because you've told someone else and you expect them to not share it (in the sense of "can you keep a secret?"). Clearly there's not a common understanding of these simple words. Seems to me that Dan's mini-rant was referring to "privacy" in the sense you define it above (controlling spread of info already held by others). - RL "Bob"