[cap-talk] The Cascade Problem viewed as a Permission vs. AuthorityDistinction

[Karp, Alan H]

Toby Murray wrote:
> 
> Alan, is there a paper on VOC? It's come up here a few times 
> and I know 
> there's some E code in MarcS' Walnut that demonstrates it but 
> I've not 
> yet been able to get my head around this code. Is there 
> something that 
> indicates the basic idea of VOC and how it might be 
> implemented in the 
> general object-cap model?
> 
Nothing written on VOC because we didn't understand its significance at
the time we did it.  MarkM, MarcS, and Ping picked up on it when I went
through the Client Utility tutorial with them. 

Object capabilities can only implement some of VOC.  In E, you use what
MarkM calls the "Loan Officer Protocol" from the Bob Hope joke that a
bank will only give you a loan if you can prove that you don't need it.
Alice invokes Bob with a reference to Carol.  The reference to Carol is
replaced by a null unless Bob already has a reference to Carol.

________________________
Alan Karp
Principal Scientist
Virus Safe Computing Initiative
Hewlett-Packard Laboratories
1501 Page Mill Road
Palo Alto, CA 94304
(650) 857-3967, fax (650) 857-7029
https://ecardfile.com/id/Alan_Karp
http://www.hpl.hp.com/personal/Alan_Karp
  
  
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