Yes, the problem of an authenticator providing different identities to the peer and the server is the typical channel binding problem and can be detected by simply doing a protected exchange of the identity between the peer and server. When such a discrepancy is detected, then, keys won't be handed out or if the identity is part of the key derivation, then, it will result in a key mismatch anyway. Hence, there is no problem there. In my understanding, Dan's claim is that the server is unable to detect that an authenticator is claiming an incorrect identity and by virtue of that, if the authenticator claims the false identity to both the peer and the server, a key will be provided to the authenticator and that will match the key that the peer derives, even if the identity was part of the key derivation. This is the problem that I have detailed in my earlier email and I belive that can be resolved with the text I proposed. Regards, Vidya > -----Original Message----- > From: Lakshminath Dondeti [mailto:ldondeti@xxxxxxxxxxxx] > Sent: Saturday, February 17, 2007 9:36 AM > To: Sam Hartman > Cc: Narayanan, Vidya; bernarda@xxxxxxxxxxxxx; Dan Harkins; > ietf@xxxxxxxx > Subject: Re: comments on draft-houseley-aaa-key-mgmt-07.txt > > Sam, > > The problem of an entity in the middle giving disparate > information to the peer and the server is in fact easier to > solve than the problem Vidya summarized. The disparate > information problem has been described in the EAP Keying > Framework document and elsewhere too. > > To my understanding, we are beyond that point in the > discussion in HOKEY and considering the new case of the > entity in the middle lying to both sides and attempting to > get a key that another entity in the middle is supposed to get. > > Let me put it this way, both issues are considered problems > to address/solve in this case. > > regards, > Lakshminath > > Sam Hartman wrote: > > Vidya, I found the model you proposed didn't fit what Dan > was talking > > about very well. In particular, Dan wants to focus on problems > > resulting from the fact that the name of the authenticator used > > between the peer and the authenticator may be different > than the name > > of the authenticator used between the authenticator and the AAA > > server. That distinction did not figure prominently enough in your > > argument that I could tell whether you and Dan are talking > about the > > same thing nor whether I could even tell if I agreed with you. I'd > > recommend refocusing your model on this distinction; I > think once you > > do we may well make significant progress on discussing a > long-standing > > issue. > > > > --Sam > > > > > > _______________________________________________ > > Ietf mailing list > > Ietf@xxxxxxxx > > https://www1.ietf.org/mailman/listinfo/ietf > > > _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf