Subject: [quicwg/base-drafts] e7f470: Update key schedule

From: Martin Thomson <[email-masked]>
Date: Thu, 07 Dec 2017 20:52:26 -0800

Branch: refs/heads/gratuitous-key-schedule-change
  Home:   https://github.com/quicwg/base-drafts
  Commit: e7f4707d3864a2e63e7d68dd81be85d99dca4134
      https://github.com/quicwg/base-drafts/commit/e7f4707d3864a2e63e7d68dd81be85d99dca4134
  Author: Martin Thomson <[email-masked]>
  Date:   2017-12-08 (Fri, 08 Dec 2017)

  Changed paths:
    M draft-ietf-quic-tls.md

  Log Message:
  -----------
  Update key schedule

This changes the labels that we use in key derivations to be shorter.  That is
in line with similar changes TLS made, so that the number of iterations of the
underlying hash function are reduced slightly.  QUIC will still run SHA-256
like a bitcoin rig, but this should help some.

I've chosen to define the function we use rather than reuse the TLS 1.3
function.  It's still the same function, but it now uses a different root
label.  That should help avoid collisions if QUIC and TLS diverge (though that
would be unlikely).  The main benefit is in reducing the label length.

This also corrects the error in the example.

  Commit: 7ebcc7a710b574616112f961406e75fb846c131e
      https://github.com/quicwg/base-drafts/commit/7ebcc7a710b574616112f961406e75fb846c131e
  Author: Martin Thomson <[email-masked]>
  Date:   2017-12-08 (Fri, 08 Dec 2017)

  Changed paths:
    M draft-ietf-quic-tls.md

  Log Message:
  -----------
  A few consistency fixes

Compare: https://github.com/quicwg/base-drafts/compare/e7f4707d3864^...7ebcc7a710b5