Re: Loops (RE: CPIM changes)

Dave Crocker <[email protected]> writes:

> if one side of the gateway uses key/value and the other side uses compact
> binary, then how does end-to-end security work?

The Signature is over the canonical form, but that form is NOT
necessarily the form transmitted over the wire.  The canonical form is
key/value, so the signature is over the key/value form.  However, the
IM system can then send out a compact-binary representation, and the
receiver re-translates into the canonical key/value form in order to
verify the signature.

The question you SHOULD have asked is how does _encryption_ work?  In
that case you do need to encrypt the canonical form.

Note that this is exactly why you need to duplicate the IM Transport
Headers in the message/CPIM object.

> d/

-derek

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       [email protected]                        PGP key available



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