eap Mailing List: Re: channel binding

[Jari Arkko (jari.arkko]

Salowey, Joe wrote:

> I don't think confidentiality is strictly necessary if one is
> transmitting a MAC of blob of data (type 1).  In GSS-API channel
> bindings explicitly state that the underlying mechanism may not provide
> confidentiality so applications must take this into consideration when
> providing channel binding data. 
>  
Yes.

> If type 2 channel bindings are in use where data must be available on
> the other side confidentiality is more of a consideration.
>  
This would depend on the type of data being communicated.
Type of service, identities of parties would be visible in the EAP
exchange. Whether that's a problem depends on many things,
including what the lower layer (both aaa and l2) does. Lets say
that a future l2 has some kind of a support for hiding some of
the identities involved in a network attachment. Now, if it
also protects the EAP exchange then it doesn't matter if channel
bindings are not encrypted. But if it doesn't protect EAP, then
secure information from l2 may leak out via EAP.

Also, if we develop channel bindings capability for a
parameter set now, we don't know what it will be used later
for.

--Jari