From: Jim choate <ravage@bga.com>
The problem I see with this is that there is no connection between a black holes mass and surface area (it doesn't have one). In reference to the 'A' in the above, is it the event horizon? A funny thing about black holes is that as the mass increases the event horizon gets larger not smaller (ie gravitational contraction).
Actually black holes do have a defined surface area, which is basically, as you suggest, the area of the event horizon. And of course this is larger for more massive black holes, as you say. I believe the Bekenstein bound is based on reasoning that suggests that if the state density of a region exceeds that bound, it will essentially collapse into a black hole and be inaccessible to the rest of the universe. The surface area in that context can be the conventionally defined area. To bring this back to crypto a bit, the point of this discussion was that there can be only a finite amount of processing done in finite time by a finite-sized machine, even when QM is taken into consideration. Note, though, that this result appears to require bringing in quantum gravitation, a very poorly understood theory at present. Hal