Re: [TLS] Comments on draft-wood-tls-external-psk-importer-01

"Christopher Wood" <> Wed, 10 April 2019 01:36 UTC

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Date: Tue, 09 Apr 2019 21:36:04 -0400
From: "Christopher Wood" <>
To: "John Mattsson" <>, "" <>
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Subject: Re: [TLS] Comments on draft-wood-tls-external-psk-importer-01
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Hi John,

On Tue, Apr 9, 2019, at 11:53 AM, John Mattsson wrote:
> Hi Chris,
> Thanks for the discussion. Would be good if a future version:

Likewise -- thank you for the comments!

> - Made clear if the imported PSKs MUST NOT / SHOULD NOT / MAY / SHOULD 
> / MUST be offered alongside the existing external PSKs. While offering 
> both would make a migration path possible I don’t think it is the way 
> to go.

Yep, we'll clear this up. (I'm currently leaning towards *not* allowing it.)

> - If MUST NOT, the document should maybe also state what the client do 
> if it receives a unknown_psk_identity alert, is it allowed to try again 
> with the external (non-imported identity) or is it forbidden to do so?

Good question! I'll file an issue to track and resolve this. 

> - Made clear if use of draft-wood-tls-external-psk-importer is a 
> property of the TLS implementation (i.e. used on all PSK) or a property 
> of the external PSK (i.e. only used on keys with this property).

It's the former, for all external PSKs. We'll try to clarify this.

> - State that "tls12" is used for DTLS 1.2 and "tls13" is used for DTLS 1.3.


Thanks again for the comments and review.