On Thu, 19 Oct 2000, Bill Stewart wrote:
At Tue, 17 Oct 2000 17:39:13 -0700 Nathan Saper <natedog@well.com> wrote Unless I'm mistaken, there is no essential physical law that determines computing power, exploits of algorithms, etc. The same cannot be said for speed-of-light travel.
Data storage probably requires at least an atom, or at least one electron, or at least one quark. There are only so many spare ones of these in the universe.
Yes, you do need at least one, but perhaps you _only_ need one. Check out the story in EETimes at http://www.eet.com/story/OEG20000831S0019
There have also been calculations on energy requirements for computation (don't remember the rationale; probably in Schneier 2nd Ed.)
<sigh> People seldom read the errata for books.
* Page 157: The section on "Thermodynamic Limitations" is not quite correct. It requires kT energy to set or clear a single bit because these are irreversible operations. However, complementing a bit is reversible and hence has no minimum required energy. It turns out that it is theoretically possible to do any computation in a reversible manner except for copying out the answer. At this theoretical level, energy requirements for exhaustive cryptanalysis are therefore linear in the key length, not exponential. -Ryan -- Ryan McBride - mcbride@countersiege.com Systems Security Consultant Countersiege Systems Corporation - http://www.countersiege.com