Re: [TLS] Version in record MAC

Russ Housley <housley@vigilsec.com> Mon, 19 October 2015 22:25 UTC

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From: Russ Housley <housley@vigilsec.com>
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Date: Mon, 19 Oct 2015 18:24:30 -0400
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To: Eric Rescorla <ekr@rtfm.com>
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Subject: Re: [TLS] Version in record MAC
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Option #2 seems fine to me.

Russ


On Oct 19, 2015, at 12:28 PM, Eric Rescorla wrote:

> Folks,
> 
> https://github.com/tlswg/tls13-spec/issues/278
> 
> The additional data field presently includes the version:
> 
>       additional_data = seq_num + TLSPlaintext.record_version
> 
> However, TLSPlaintext.record_version is now always {3, 1}, so
> this is redundant. There seem to be two primary options here:
> 
>      1. Don't MAC the version at all.
>      2. MAC the negotiated version (which should be clear at
>         this point).
> 
> I could go either way on this (slightly leaning towards #2) but
> the current thing seems silly.
> 
> -Ekr
> 
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