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Re: Groups



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At 12:03 PM 12/18/96 EST, Ron Rivest wrote:
>
>In SDSI, a group can be defined with (1) membership certs, or (2) group
>definition certs (which give a formula for group membership).  As usual, the
>default is that membership needs to be affirmatively established in one of
>these two ways.  It is not required that the two approaches be consistent
>(an issuer can make someone a member by issuing a group membership cert,
>without having to modify the formula for the group definition).  
>
>A membership cert can grant membership to a key, or to a name.  I don't
>understand your question below regarding "person certs" vs "member certs",
>unless you are just referring to the two ways membership certs can be issued.
>They were both intended...
>
>Let me know if this doesn't answer your question...

Ron,

	I think you answered my question.

	After reading the SDSI paper, I had populated the SDSI name universe in my 
mind with individual names and group names -- somehow different but 
indistinguishable in practice.  I had distinguished them in my own mind 
based on the kind of certificate one finds using each.  A "person cert" was 
<name,key> defining a SDSI name as an individual.  A "member cert" was one 
declaring group membership.

	I hadn't considered the possibility that a group could be defined without 
referring to membership at all -- just by mapping the same name to multiple 
keys.

 - Carl

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