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Re: Comments on "Hybrid Auth. mode for IKE"
In message <v03110700b1e2448c6f64@[128.89.0.110]>, Stephen Kent writes:
>
> User's with passwords can be issued certs readily.
This is a very important point. Rather than touching ipsec and IKE,
a better solution would be to define a certificate retrieval/generation
protocol. That is, suppose a user has a "conventional" authentication
mechanism, such as a password or a token. Use that mechanism to contact
a server that will send you your stored certificate. If you don't have
one, a short-lived certificate, suitable for use with IKE, can be
generated for you on the fly. Its lifetime can be whatever is
appropriate; if something like 4-8 hours, it need not use high-quality
RSA moduli since ipsec will provide perfect forward secrecy.
If I were to design such a protocol, I'd probably use something like
EKE (www.research.att.com/~smb/papers/neke.ps or .pdf; also aeke.{ps,pdf})
to provide protection against password-guessing. (Disclaimer -- EKE and
AEKE are patented.) Or the client can generate a certificate on the
fly, and send the public portion off to the server, along with an
authenticator, to be signed. Either way, there's no need to touch
IKE.