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Re: [TLS] RFC8446 backward compatibility question

Nick Harper <ietf@nharper.org> Thu, 05 August 2021 20:46 UTC

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From: Nick Harper <ietf@nharper.org>
Date: Thu, 05 Aug 2021 13:45:46 -0700
Message-ID: <CACcvr=k1uHawbNk=fR_nOHXmEH8B56FuiOGK0nZB+HkvV_X5-g@mail.gmail.com>
To: Toerless Eckert <tte@cs.fau.de>
Cc: tls@ietf.org
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Subject: Re: [TLS] RFC8446 backward compatibility question
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Yes, backward compatibility is optional.

On Thu, Aug 5, 2021 at 1:44 PM Toerless Eckert <tte@cs.fau.de> wrote:

> I am trying to figure out if every implementation compliant with
> RFC8446 is also necessarily interoperable with an RFC5246 peer, or if this
> is just a likely common, but still completely optional implementation
> choice.
>
> I could not find any explicit statement that backward compatibility
> with RFC5246 is mandatory (but i just was doing browsing/keyword search
> over RFC8446). COnditional text such as:
>
> "implementations which support both TLS 1.3 and earlier versions SHOULD"
>
> make me think that TLS 1.2 backward compatibility is just optional.
>
> Thanks
>     Toerless
>
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