Comments: Nick Szabo - Scarce Objects

Not to go too crazy but doesn't Nick's paper replicate a governance model?

And for that matter is a receipt an object of authenticated transaction therefore representative of a scarce object being consumed or transfered?

Posted by Jimbo at June 26, 2005 03:20 PM

Nick, some comments! They are vsomewhat stream of consciousness, which may help or it may not....

I took the 1st three paras as the Abstract. That and an Intro needed, maybe.

These intro paras meander and jump around.

"Scarce objects are also a new security model. No security model to date has been widely used for distributing objects across trust boundaries.

From my pov, I'd be looking to see why/how SOs compare and exceed capabilities, that is, make that statement so! (OK, so I see this is actually
written about later on.

"This is due to THEIR ..."

'Their' refers to SOs or to every other security model?


At this point it seems to branch to a section of architectural import that starts with some odd references to physicists. There seems to be a missing header of some sort, something like "Architectural Summary" or somesuch.

It closes with a set of 3 requirements which is quite strong. Somehow this should be signalled. It's the closest it gets to definitions AFAICS.


"This architecture is "affordable" in Donald Norman's sense, since human brains are designed to reason in much more sophisticated ways about physical objects than about computational objects. ........... The intuitive physical metaphor of scarce objects is based, not on the complexities of the quantum world as understood by today's physicists, but on the intuitively clear, ideal world of the "atomists" from Democritus through Newton.

These references are obscure and look like hand waving. Unless they are explained - in the sense of the image that the names are supposed to convey, then they don't add anything, and potentially annoy the reader.

The leap from limitations and requirements (points 1,2,3) to a discussion of property rights, trust boundaries, etc, is too hard to follow. It needs a heading of its own, and/or some linkage description as to why the cross from disciplines is useful (physicists to lawyers in one paragraph...)


"With scarce objects, any computation across trust boundaries will have these properties of atomicity, conservation, composition, and the accompanying clear delineation of rights and responsibilities."

Isnt' that last thing 'property' ? Isn't that what you established in 3. above? So it would be ...

"these properties of atomicity, conservation,
composition, and property"

leaving for later text a tighter definition of each?


"Scarce objects are, in other words, online commodities. These commodities may represent, typically, rights (or expectations) to services the right to use an e-mail or news service......

A definition is needed. Scarce objects need to be defined. What are they? Here, they *MAY* represent rights or expectations or services... does this mean they *MAY* be something else as well?

"Such service rights will usually be limited by time or resource usage or number of invocations. When represented properly,..."

First off, get the basic definition down. Then list the caveats, limitations, etc...


"Such rights or codified expectations are enforced by reputation, by the physics of scarce objects, or both, in substitute for or in addition to expensive traditional legal means.

This seems to say:

Such rights or codified expectations may be enforced by a combination of
- reputation,
- the physics of scarce objects, and/or
- expensive traditional legal means.

In that the relationship between the three seems to be versatile and beyond the scope of the article.

- "not a complete model of computation" ...

if this statement has any relevance it possibly belongs in a conclusion. In order to achieve that, it seems that
a) SOs need to be clearly defined,
b) SCs need to be clearly defined,
c) the relationship between SOs and SCs needs to be clear
d) and what each can and can't do needs to be explained.
At this point, none of that is clear.

- Microeconomics - what's the point in mentioning transaction costs? Supply chains? Call graphs? Client-server ... Customer-supplier... none of this "relates" to the paper.


OK, now up to Usage Control vs. Access Control.

At this point I do not know what a scarce object is.

That is, I have no definate test, no definition, no difference from some other well known and assumed known other construct. As you know I'm quite a definitional guy, and after yonks on the capabilities group, I'm still not sure I can write down what a capability is. So this might appear overly harsh, or premature in that until I want to build one, I don't really need to know what it is.

Posted by Iang at June 29, 2005 08:35 PM
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