[cap-talk] Creating 32-bit capabilities, automatic capabilities by subclassing?

[John Carlson]

On May 10, 2006, at 5:38 AM, Sandro Magi wrote:

> John Carlson wrote:
>> On May 9, 2006, at 5:29 PM, Jed at Webstart wrote:
>>
>>>> objects.  What I envision doing is using some kind of algorithm to
>>>> generate a capabilities-as-data integer to pass over the internet
>>>> to other people.
>>> Are you talking about something like Tyler's YURLs?
>>>
>>
>> Something like that that would fit in an int (32-bits).  Is there an
>> algorithm for creating capabilities-as-data for ints?
>
> YURLs are just an unguessable number. And note that guessing a 32-bit
> number is easily within reach of modern hardware. Assuming testing  
> each
> integer takes 1ms, a conservative estimate I think, you can fully
> exhaust a 32-bit space in less than 50 days. I believe 80-bits is as
> little as you can reasonably go.

So if I want to collaborate, by building a "graph" from nodes and  
arcs, perhaps
this is how I might do it:

I need to retrieve a YURL for building a new graph,
then retrieve a YURL from the graph YURL for creating new nodes  
(probably a
Node class underneath), a similar one for arcs, then use a YURL that  
my coworker
has communicated to me to send my coworker the creation YURLs.  Then  
we can use
the creation YURLs to create object YURLs, send them to each other,  
and attach
the object YURLs to OpenGL objects.  Next I use the graph YURL to  
generate
YURLs for modifying and reading object attributes, and YURLs for
attaching nodes to arcs and arcs to nodes. I pass these to my  
coworker.  When I move an
OpenGL object, I use the object YURL and a modify YURL with  
parameters to update the database
stored on the server somewhere.   I notify  my coworker by passing  
the object YURL
with the read YURL, so that he can read the location values from the  
object in the database.
I then start attaching arcs to nodes and nodes to arcs.  I pass the  
attachment YURL with
the two objects YURLs I am attaching to the database, and to my  
coworker.  We
are now building a fairly large graph.  Oops, there's a bug.  We need  
to have
detachment YURLs and deletion YURLS.

My question is, can I get all this capability passing in my program  
by simply attaching
my source code for Nodes and Arcs and Graphs to some existing capability
classes?  Maybe there's a definition of Graphs and Arcs and Nodes  
that I can take advantage
of?  Then I need someway to securely share OpenGL attributes of Nodes  
and Arcs like, position, orientation
and color and attachments--through a web server.  Perhaps the code to  
do this would
be generated.  I would write the code for selecting and moving the  
objects through 3D.

Thanks for letting me know about recent developments.

How does one let someone know the purpose of a YURL.  Are there  
semantics that
go with it?

John