Re: [TLS] Advancing draft-ietf-tls-hybrid-design

Dan Brown <> Thu, 05 August 2021 19:22 UTC

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From: Dan Brown <>
To: Douglas Stebila <>, "" <>
CC: Shay Gueron <>
Thread-Topic: [TLS] Advancing draft-ietf-tls-hybrid-design
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Date: Thu, 5 Aug 2021 19:22:09 +0000
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Subject: Re: [TLS] Advancing draft-ietf-tls-hybrid-design
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> -----Original Message-----
> From: TLS <> On Behalf Of Douglas Stebila
> We wanted to see if there is any further feedback on our draft "Hybrid key
> exchange in TLS 1.3" ...  We have not received any new feedback from the
working group
> since we posted our last non-trivial update in October 2020.

Allowing 3 or more key exchange methods in a hybrid combination should
somehow be an option, for a user who can afford the extra cost and is
risk-averse and has high-value data to protect.
I was told this issue (2 versus 2+) was already discussed on the list, but I
must have forgotten (or missed) that conversation.

A workaround is to nest TLS into TLS, to get more types of key exchange, or
to apply the extra key exchanges at the application layer, on top of TLS,
for those (few) who want the extra security.  These workarounds imply
applying symmetric crypto twice, which does not help against the quantum

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