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Re: [TLS] PR for anti-downgrade mechanism

Dave Garrett <davemgarrett@gmail.com> Fri, 09 October 2015 20:16 UTC

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From: Dave Garrett <davemgarrett@gmail.com>
To: tls@ietf.org, Eric Rescorla <ekr@rtfm.com>
Date: Fri, 09 Oct 2015 16:15:54 -0400
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Subject: Re: [TLS] PR for anti-downgrade mechanism
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On Friday, October 09, 2015 08:23:30 am Eric Rescorla wrote:
>   https://github.com/tlswg/tls13-spec/pull/284
> 
> The idea is that if a TLS 1.3 server receives a TLS 1.2 or below
> ClientHello, it sets the top N bits of the ServerRandom to be a
> specific fixed value.
[...]
> I've written this up with 48 bits and a specific fixed value (03 04 03
> 04 03 04) but that's just a strawman and we can bikeshed on that if
> people think this is a good idea.

I support this, though I would like to know why 6 bytes was chosen instead of just 4. I don't object; I would just like to know the reasoning here.


Dave

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