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Re: Java programs, etc.



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At 01:56 PM 4/8/97 EDT, Ron Rivest wrote:
>
>I guess I wasn't clear again.  My intention in writing
>
>	(* program java <hash-of-java-program>)
>
>was to write a PREDICATE that matched a certain set of byte-strings
>(or S-expressions), just as
>	
>	(* range date 1997-01-01_00:00:00 1998-01-01_00:00:00)
>
>matching a certain set of byte strings. 
>
>I did NOT propose that the java program be one that takes intersections
>of various forms.  Indeed, I think THAT is INSECURE!

Ron,

	Matt is going to write up his version of this, but my view is that a (* 
program ...) tag set represents a set of tags (as does any other * form).  
You can do that by having a program generate a full set of tags -- maybe as 
a (* set ...) -- or you can make the program a little more intelligent.  It 
could take as a parameter one explicit (tag ) and generate the subset of its 
set of tags which intersect with the explicit tag.  It might also take a set 
of 5-tuples and generate a different set of tags depending on the input 
5-tuples.  Such a program is, in fact, what PolicyMaker does and is 
equivalent to taking intersections (or worse).  If you think this is 
insecure, then that's a topic for discussion -- especially with MAB -- but I 
don't see how to distinguish (* program ) from something that takes 
intersections.

 - Carl

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