Re: [Cfrg] When TLS is an overkill...

[Peter Gutmann <[e-mail]>]

Dr. Pala <[e-mail]>​

>I noticed that sometimes people use TLS to establish a secure channel with a
>server even when all they want to do (i.e., no extra features/checks/etc.)
>could potentially be achieved in just 2/3 messages. An example of this is EAP
>- whenever a secure channel needs to be established, EAP-TLS, EAP-TTLS, EAP-
>TEAP, etc. must be supported to tunnel the 2nd method that will be used for
>authentication.

That's because it's required for EAP, which in the form of EAP / RADIUS is the
universal standard for device authentication.  There are (at least) tens of
billions of devices that use this somewhere.  It's not used because it's a
technically good solution (running EAP over DIAMETER over EAP-TLS over EAP
over RADIUS over UDP is probably close to insane), but because there's a vast
global infrastructure that supports it.

>My question for the group is: if we were to use a "simple" way to establish
>the secure channel, are there recommendations for what should be in those
>messages ? What would be the minimum set of required data that MUST be
>included in the exchange ?

Also, what colour should the various pieces be painted, and should it be
gloss, satin, or matt?

You're asking the wrong question(s).  What problem are you trying to solve?
Without that frame of reference, it's not possible to answer any of the
questions you're asking.

If you want an example of some designs that do a good job of solving a
particular problem, look at LoRaWAN security or WireGuard.  They solve a
specific, widely-encountered problem, and they do a pretty good job of it
without adding a ton of unnecessary bloat.

Peter.