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Re: Corporate Key mechanism

1998-01-23 14:52:19
On Fri, 23 Jan 1998, phil wrote:

-> I would word it differently, I would instread say that what we wish to do is
-> to define an attribute which defines a KEY, not a certificate to which the
-> message SHOULD also be encrypted.
-> 
-> The reason for prefering a key over a certificate is that all the
-> information is provided in a single package. The purpose of the certificate
-> is to perform identity binding to the key. I would like a direct binding to
-> what our PGP friends would call a 'mobby key'.

... which could be the competitor's key! Or, a bogus key that has a small
"mistake" and will turn out to unseful or outdated when needed. How can
someone trust a key without trusted information on the key, as provided by
a cert which is signed by a trusted issuer or as provided by an "insider"
mechanism also trusted? Mind you, the trusted cert can be a self-signed
cert very well because trust on that cert is out-of-band ("Towards a
real-world model of trust" http://mcg.org.br/trustdef.txt). 

The mistake was in the reasoning that a key is all you need. A key is only
data with almost zero syntax (yes, you can guess it is a RSA-key but there
is no clue on the message digest used) and zero semantics. Of course, if
you think about implict certs, where the value of the key itself is a
pointer to the cert as known by a restricted community, then to that
restricted community the key is the DN to the one and only cert -- which
again unfolds the rest of the syntax and all the semantics you need in
order to trust that implict key.

In other words and taking my pick at an old joke, the important thing is
not what language God used when He computed the world, but what was His
makefile! The hidden dependencies in Nature are the hidden semantics which
we would need in order to understand it -- and the same goes for keys
where the certificates they are imbedded in (even implicit certs) carry
information which is essential to their use (even knowing it has no
semantics is useful). 

Maybe what you need is just a proper .forward or aliases file and S/MIME
as it is.

Cheers,

Ed

______________________________________________________________________
Dr.rer.nat. E. Gerck                     
egerck(_at_)novaware(_dot_)cps(_dot_)softex(_dot_)br
http://novaware.cps.softex.br
    --- Visit the Meta-Certificate Group at http://mcg.org.br ---





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