I just dug through some archived e-mail in which someone disputed the notion of equating physical entropy with information entropy. I don't have any good physics books handy (lots of stuff is in storage while we struggle through a home restoration project) so I can't vouch for the argument. However, it sounds like it has some merit and seems consistent with my own dusty recollections of modern physics. So, we should probably add the following to the glossary entry: Some physicists dispute this concept, arguing that physical entropy provides at best an "analogy" for information entropy. While it is true that both are defined in terms of fundamental states, physical entropy is also defined in terms of the probability space of each state. But I'm still contemplating whether it might be interesting to quantify brute force attacks in terms of megawatt-hours or solar-power-years or (by converting energy terms to mass) as tons of anti-matter. If we ever break the barrier, it gives us a new sort of Mach number, I guess. (a "Shannon" ??) Rick. smithat_private "Internet Cryptography" at http://www.visi.com/crypto/
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 13:58:29 PDT