Re: [Ace] [EXTERNAL] Re: call for adoption for draft-marin-ace-wg-coap-eap

I’d like to second the question Mohit assumes Michael is asking:

What is the benefit, in the context of IoT, to add the overhead of EAP to say TLS?

/Ludwig

From: Ace <ace-bounces@ietf.org> On Behalf Of Mohit Sethi M
Sent: den 22 januari 2021 15:37
To: Michael Richardson <mcr+ietf@sandelman.ca>; Ace Wg <ace@ietf.org>
Subject: [EXTERNAL] Re: [Ace] call for adoption for draft-marin-ace-wg-coap-eap

Hi Michael,

I guess the question you are asking is: what is the benefit of adding the overhead of EAP. For EAP-TLS, you could directly use TLS. For EAP-pwd (which is a PAKE) one could use any PAKE without the EAP encapsulation overhead?

Is your concern only in the context of IoT or do you think in general we are better off using protocols directly without the EAP framework overhead?

--Mohit
On 1/21/21 5:26 PM, Michael Richardson wrote:

I reviewed the document before, and my concerns were not really answered.

I can not understand what the applicability is.

The document starts off with:

   The goal of this document is to describe an authentication service

   that uses the Extensible Authentication Protocol (EAP) [RFC3748].

   The authentication service is built on top of the Constrained

   Application Protocol (CoAP) [RFC7252] and ALLOWS AUTHENTICATING TWO

   CoAP endpoints by using EAP without the need of ADDITIONAL PROTOCOLS

   TO BOOTSTRAP A SECURITY ASSOCIATION BETWEEN THEM.

...

   The assumption is that the EAP method transported in CoAP MUST

   generate cryptographic material [RFC5247]

This implies use of one of the many EAP-TLS modes, some EAP PAKE

mode, or maybe, in theory some EAP-SIM/AKA mode.

1) TLS modes could just use TLS, or DTLS and omit the extra EAP

   bytes.  If saving those bytes are not important, then

   the use of PANA seems to do the same thing.

2) The EAP PAKE modes could just TLS with some PSK or PAKE

   authentication.

3) The EAP-SIM/AKA modes are not realistic, as they generally depend upon

   being able to talk to a database of SIM/AKA secrets.

So, which modes that generate cryptographic material are envisioned?

The document goes on to say:

   The CoAP client MAY contact

   with a backend AAA infrastructure to complete the EAP negotiation as

   described in the EAP specification [RFC3748].

which is a third party, when the intro told me that no third party was

required.  Even figure 1 show three parties.

And section 5 says there might be five parties, again including an AAA server.

I believe that this entire proposal goes against the ACE architecture,

and should not be adopted by this WG.

This work seems to duplicate the work in LAKE, as well as cTLS, while not

bringing any clear advantage over existing protocols.

If adopted, I don't review the document.

--

]               Never tell me the odds!                 | ipv6 mesh networks [

]   Michael Richardson, Sandelman Software Works        |    IoT architect   [

]     mcr@sandelman.ca<mailto:mcr@sandelman.ca>  http://www.sandelman.ca/        |   ruby on rails    [

--

Michael Richardson <mcr+IETF@sandelman.ca><mailto:mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )

           Sandelman Software Works Inc, Ottawa and Worldwide

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