Subject: [SIP] [Fwd: [Sip-implementors] Message integrity with digest]

From: Carmelo Zaccone <[email-masked]>
Date: Mon, 09 Apr 2001 11:53:56 +0200

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  Indigo                         Carmelo Zaccone             
    Software                       Head Software Engineer  
                                                           
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Subject: Re: [Sip-implementors] Message integrity with digest
From: Jonathan Lennox <[email-masked]>
To: Carmelo Zaccone <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Date: Thu, 5 Apr 2001 13:07:11 -0400 (EDT)

On Thursday, April 5 2001, "Carmelo Zaccone" wrote to "[email-masked]" saying:

> 	As you know, the 'qop=auth-int' alternative that the 
> 	digest scheme defines, offers a mechanism to have
> 	the message integrity security feature in our 
> 	transactions. 

[...]

> 	So, in SIP I would propose extending the way we use the digest 
> 	integrity mechanims to map the PGP message integrity coverage.
> 	i.e. extending the entity body signification by defining it as
> 	everything that follows the Authorization/ProxyAuthorization
> 	headers as defined in chapt. 14.1.2 for the pgp-signature.

A much cleaner (though more bandwidth-intensive) way of solving this
problem would be to define a 'message/sip' MIME type, which duplicates all
the end-to-end headers and includes the body, and then run auth-int
integrity checking over *that*.  Headers inside the message/sip body 'win'
over the headers in the authenticated body.  This is much more robust in the
presence of intermediate proxies which might mangle or re-order headers.

A 'message/sip' MIME type would also lets us use S/MIME and PGP/MIME
authentication and encryption on message headers.

This discussion should maybe move to the main sip list?

-- 
Jonathan Lennox
[email-masked]