Dean, > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Dean Willis > Sent: 30 March 2009 19:18 > To: Hadriel Kaplan > Cc: SIP List; Francois Audet; Jon Peterson > Subject: Re: [Sip] francois' comments and why RFC4474 not > used in the field > > > On Mar 30, 2009, at 1:00 AM, Hadriel Kaplan wrote: > > > > > > >> -----Original Message----- > >> From: [email protected] [mailto:[email protected]] > On Behalf > >> Of Dean > >> Willis > >> Sent: Monday, March 30, 2009 12:09 AM > >> > >> The MAIN reason, it seems to me, to want to change the SDP (and > >> especially the key fingerprint) undetectably is to enable intercept > >> (lawful or otherwise) without detectability. That just won't do. > > > > No, that's not at all the main reason. RFC4474 is already not end- > > to-end. It's signed by a middlebox in the originating domain, and > > verified by a middlebox in the terminating domain. There is ample > > opportunity to change the SDP at either of those domains to > perform > > lawful intercept. > > RFC 4474 can be used end to end. It all depends on which cert > is used > to sign the identity, where that signing occurs, and where it gets > checked. For stupid legacy phones, it can be signed and checked at > middleboxes operating under some level of transitive trust. For > smarter devices, it happens in the endpoint. > > Signing and checking at the endpoint, coupled with the DTLS > fingerprint check. enables end-to-end verification of media > integrity > and privacy. Once you start ripping these signatures out in > the middle > of the network and replacing them, we have lost this absolutely > critical property. If transit providers even think it MIGHT be > reasonable to rip out the signatures, then we have lost the key > functionality. Removing signatures MUST BE FORBIDDEN. Adding > new ones > might be ok. > > I might be willing to compromise on the mechanism (I've already > proposed several potential approaches to doing so), but I'm > unwilling > to compromise on the fundamental requirement for this end-to-end > applicability. [JRE] Yes, that is a positive feature of RFC 4474, the fact that it can be used end-to-end, end-domain-to-end-domain, or even end-domain-to-end or end-to-end-domain. In other words, the authentication and verification functions can be in the endpoint or an end domain intermediary.
John > > -- > Dean > _______________________________________________ > Sip mailing list https://www.ietf.org/mailman/listinfo/sip > This list is for NEW development of the core SIP Protocol > Use [email protected] for questions on current sip > Use [email protected] for new developments on the application of sip > _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [email protected] for questions on current sip Use [email protected] for new developments on the application of sip
