[TLS] PR #699: Simplify traffic key expansion

Eric Rescorla <ekr@rtfm.com> Mon, 17 October 2016 20:09 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 17 Oct 2016 16:08:33 -0400
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Subject: [TLS] PR #699: Simplify traffic key expansion
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Hi folks,

https://github.com/tlswg/tls13-spec/pull/699/files

A while back Steven Valdez pointed out that now that we have the PSK binder
change and dual key ladders, each set of traffic keys is generated from a
different
base secret which has a label folded in [0], so we don't need to have the
"phase" parameter in the traffic key calculation in Section 7.3, which
simplifies things
a bit. Due to an oversight, this didn't make it into the PR, but it seems
straightforward.

Please let me know ASAP if I have missed something here or you otherwise
object.

-Ekr


[0] client_early_traffic_secret, [sender]_handshake_traffic_secret,
[sender]_traffic_secret_N respectively