[TLS] Explicit use of client and server random values

John Foley <foleyj@cisco.com> Wed, 16 December 2015 16:12 UTC

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From: John Foley <foleyj@cisco.com>
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Date: Wed, 16 Dec 2015 11:12:42 -0500
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Subject: [TLS] Explicit use of client and server random values
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I apologize if this topic was previously discussed, I've only recently 
joined the TLS mailer list.  While reviewing the TLS 1.3 draft (revision 
10), section 7 begins with the following wording:

    In order to begin connection protection, the TLS Record Protocol
    requires specification of a suite of algorithms, a master secret, and
    the client and server random values.

However, when reading through all of section 7, there appears to be no 
explicit use for the client and server random values.  While these 
values would be used implicitly when the handshake messages are hashed, 
and thus have bearing on the key schedule calculation, there appears to 
be no explicit use of the client and server random values similar to 
section 6.3 in the TLS 1.2 spec.

Am I interpreting this properly?  If the client and server random values 
are no longer explicitly used in any key derivation logic, maybe this 
should be noted in section 6.3.1, as implementors will no longer need to 
parse these values when processing incoming messages.  Additionally, the 
intro to section 7 is misleading to implementors, as it implies the 
client and server random values are needed to derive the key schedule.

The following issue and PR appear to be related to my question:

https://github.com/tlswg/tls13-spec/issues/185
https://github.com/tlswg/tls13-spec/pull/189