Re: [Emu] WG last call for draft-ietf-emu-tls-eap-types ?

[Alexander Clouter <[e-mail]>]

Hello,

On Tue, 20 Sep 2022, at 20:50, Alan DeKok wrote:
>
>> Section 2.2 - TEAP
>> ------------------
>> I do not think changing the language for the definition of the MAC used for the Compound MAC was necessary.
>
>   I don't see if changing the definition that much,  There's just a 
> reference to the previous section, which was changed.  That definition 
> was just changed to use TLS-Exporter() instead of TLS-PRF().
>
>   Are there any other changes which need highlighting (or fixing) ?

I got (probably needlessly) hung up on the wording "The TEAP Compound MAC defined in RFC7170 Section 5.3 is updated..." when nothing has changed there other than MAC.

Maybe: "The TEAP Compound MAC defined in [RFC7170] Section 5.3 remains but the message authentication code (MAC) for TLS 1.3 is computed with the HMAC algorithm negotiated for HKDF in the key schedule, as per section 7.1 of RFC 8446.  That is, the MAC used is the MAC derived from the TLS handshake."

I don't think CMK/Compound-MAC needs to be included here, though maybe arguably as most of the definitions at this point have been included, you may as well include the rest for completeness.

>> If any wording changes need to be made, maybe to be more explicit in stating "the MAC from the handshake" or "cipher_suite from RFC8446 section 4.1.3"? I find the existing "section 7.1 of RFC 8446" wording unusable to someone trying to answer "what am I actually meant to do here?"
>
>   Do you have explicit text to suggest?

I think your "That is, the MAC used is the MAC derived from the TLS handshake." covers this, thanks.

Cheers