Re: [TLS] Static DH timing attack

Dan Brown <danibrown@blackberry.com> Thu, 10 September 2020 15:18 UTC

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From: Dan Brown <danibrown@blackberry.com>
To: "Salz, Rich" <rsalz=40akamai.com@dmarc.ietf.org>, "tls@ietf.org" <tls@ietf.org>
Thread-Topic: Static DH timing attack
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Date: Thu, 10 Sep 2020 15:17:59 +0000
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Subject: Re: [TLS] Static DH timing attack
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From: TLS <tls-bounces@ietf.org> On Behalf Of Salz, Rich
> Do we need a short RFC saying “do not use static DH” ?

 

Don’t TLS 0-RTT and ESNI/ECH via HPKE use a type of (semi)static ECDH? If so, then an RFC to ban static (EC)DH in TLS would need to be very clear about not referring to these use cases of static ECDH.

 

My 2c. What about combining static ECDH (instead of signatures) with ephemeral ECDH, e.g. for more fully deniable authentication?  (ECMQV does this.)  (Perhaps this is also similar to the KEMTLS proposal for PQC, https://ia.cr/2020/534 - still need to study that.)

 

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