Re: WG Review: Recharter of IP Security Maintenance and Extensions (ipsecme)

[Jari Arkko <[e-mail]>]

Pasi,

(Adding the working group mailing list to the discussion; previous 
discussion has been at [e-mail].)

> You're right that implementing a "weak shared secret" EAP method (both
> the EAP peer and EAP server roles) on both IPsec nodes, combined with
> the "EAP mutual authentication" work item (also in the new charter)
> could be used in this situation, and would result in roughly the same
> functionality (perhaps with slightly more roundtrips/other overhead --
> but that's probably not a critical factor here).
>   

OK. And yes, I agree about the significance of roundtrips.

> NEW:
>    However, user-configured shared secrets are still useful for many
>    other IPsec scenarios, such as authentication between two servers
>    or routers. These scenarios are usually symmetric: both peers know
>    the shared secret, no back-end authentication servers are involved,
>    and either peer can initiate an IKEv2 SA. While it would be
>    possible to use EAP in such situations (by having both peers
>    implement both the EAP peer and the EAP server roles of an EAP
>    method intended for "weak" shared secrets) with the mutual
>    EAP-based authentication work item (above), a simpler solution may
>    be desirable in many situations.
>   

This formulation is better than what we had previously. I can live with 
this.

But for the record, I am still surprised that I am the only one worried 
about this. In my view this additional solution, while perhaps simpler 
on its own, will increase code size and complexity for most 
implementations. For instance, a device that serves remote access 
clients has to implement at least parts of EAP. To support 
gateway-gateway weak secrets it now has to add support for another, 
completely different authentication mode and associated configuration 
mechanisms & policies. Architecturally, it would be better to rely on 
few general solutions than to build special case "simpler" solutions 
that taken together, actually become more complex. Not to mention the 
impact on interoperability.

Jari