[TLS] Diversification with multiple inputs

"Martin Thomson" <mt@lowentropy.net> Thu, 21 November 2019 03:10 UTC

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Date: Thu, 21 Nov 2019 11:09:52 +0800
From: "Martin Thomson" <mt@lowentropy.net>
To: "Jonathan Hoyland" <jonathan.hoyland@gmail.com>, tls@ietf.org
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Subject: [TLS] Diversification with multiple inputs
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If we do the caveman thing and concatenate inputs to HKDF-Extract, what do you think we should do to the rest of the key schedule to ensure that there is diversity?

In the PSK importer draft, we use a different binder label.  Do we need diversification if there could be multiple inputs later in the key schedule?  Or is that a problem unique to PSKs?