[cap-talk] Capability accounting - meta

[Ian G]

Jed at Webstart wrote:

>>>I believe the existence of systems like PayPal argue that an IT
>>>"account" model can work in the general Internet world.  The relevant
>>>question for me is whether any sort of "capability" mechanism (with a
>>>communicable authority token for an account) makes sense, adds 
>>
>>value, can work.
>>
>>Do you mean - capabilities used to deliver / build money?
> 
> 
> I think the answer is "yes".  I understood you to suggest
> that an accounting system with ready exchange mechanisms
> (e.g. to other account systems, to real money) is itself a
> money delivery system.  Since a capability "account"
> can certainly be used in such a way and used to set
> up exchange mechanisms, it seems to me the answer is
> "yes".
> 
> 
>>If that, I would have to say yes, because it
>>is (I think) what I do.  I use capabilities or
>>capability-like constructs as the base concept
>>for a money and assets system.
>>
>>(As a sort of funny aside, the reason for joining
>>this group was to find out if that was a true
>>statement.)
> 
> 
> Interesting.  I assume you concluded that it is?

Somewhat, Not 100%.  You might recall long discussions
in the past trying to work out what a capability is;
I got close at one point but never quite nailed it.

The stuff I do is basic client-driven nymous public-
key based.  So, a client creates a key and registers
it at the server.  Then, a bunch of operations can
be written for that key, cooperating between the
client and server.

In the sense that the key can be used to pass on
resources to others, it is capabilities like, but
we do not use it in that way.  Rather, the key
has a payment operation, and can instruct a pay
from alice to bob of some amount.

The reason for this as opposed to say some sort
of caps mechanism is accounting.  When dealing with
money, a system / provider has to be exact.  It
is ok for a client to be loose, but not ok for the
system or server to be loose.  At any time there
should be exact quantification.  (Revocation of a
stuffed money transfer is needed for example.)

(This can be seen as a rejection of the [blinded]
coins paridigm, where the server can't help you
state where your coins might be.  If you like,
although my system also handles coins for those
circumstances where they make sense.)

(And, the coins paridigm might be considered to
be closer to the caps idea, in they they are
handed around and they are their own value /
control.  I'm not sure that's a useful notion
however, as one could say the same thing about
the payment instructions.)

iang