Subject: [Emu] Alissa Cooper's No Objection on draft-ietf-emu-eap-tls13-13: (with COMMENT)

From: Alissa Cooper via Datatracker <[email-masked]>
Date: Wed, 06 Jan 2021 10:15:59 -0800

Alissa Cooper has entered the following ballot position for
draft-ietf-emu-eap-tls13-13: No Objection

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COMMENT:
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Section 2.1.3:

     “When NAI reuse can be done without privacy implications,
   it is RECOMMENDED to use the same anonymous NAI in the resumption, as
   was used in the original full authentication.  E.g. the NAI @realm
   can safely be reused, while the NAI ZmxleG8=@realm cannot.”

I think it would help to make this recommendation more specific. Does “without
privacy implications” mean without the username part? Or does it mean something
else?

Should this text reference RFC 7542 for further context?

Section 5.7:

“Where a good decision is unclear” —> “Where the decision is in doubt” (or
something like that; it isn’t obvious what a “good” decision is)

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From: Mohit Sethi M <[email-masked]>
Date: Fri, 8 Jan 2021 09:00:30 +0000

Hi Alissa,

Thanks for your review. I think this commit should address your 
comments: 
https://github.com/emu-wg/draft-ietf-emu-eap-tls13/commit/69dab07b0b1c4dbb303e757c7e06ec6f4775e960

I have also explained the changes made in-line.

--Mohit

> https://datatracker.ietf.org/doc/draft-ietf-emu-eap-tls13/
The text is now updated to "When NAI reuse can be done without privacy 
implications, it is RECOMMENDED to use the same anonymous NAI in the 
resumption, as was used in the original full authentication [RFC7542].  
For example, the NAI @realm can safely be reused since it does not 
provide any specific information to associate a user's resumption 
attempt with the original full authentication.  However, reusing the NAI 
P2ZIM2F+OEVAO21nNWg2bVpgNnU=@realm can allow a potential attacker to 
associate a resumption attempt with the original full authentication."
> something like that; it isn’t obvious what a “good” decision is)
The text is now updated to : " If a safe decision is not possible, 
EAP-TLS servers SHOULD reject the resumption and continue with a full 
handshake."