Re: [Emu] WG Last Call for Using EAP-TLS with TLS 1.3

Alan DeKok <aland@deployingradius.com> Fri, 07 May 2021 22:02 UTC

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From: Alan DeKok <aland@deployingradius.com>
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Date: Fri, 7 May 2021 18:00:33 -0400
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To: Joseph Salowey <joe@salowey.net>
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Subject: Re: [Emu] WG Last Call for Using EAP-TLS with TLS 1.3
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On May 7, 2021, at 5:18 PM, Joseph Salowey <joe@salowey.net> wrote:
> [Joe] I think the one issue that was raised during TLS review was that using the same label for MSK and EMSK could make it more difficult to separate out the derivations of these keys at the TLS level.  For example, example, perhaps the TLS implementation could restrict access to the MSK and EMSK independently depending upon hte caller.

  I'll have to think about that a little more before I understand the underlying objection.

  From what I can see, MSK and EMSK are specific to EAP-TLS.  They are derived in the EAP-TLS application, by passing EAP-TLS parameters to TLS key exporters.

  So the TLS layer has no concept of what MSK or EMSK are.  As a result, the TLS layer should have minimal input into what those keys are, or how they are derived.

  Alan DeKok.