Re: [TLS] supported_versions in TLS 1.2

[Peter Saint-Andre <[e-mail]>]

Hi David, thanks for your feedback.

On 11/19/21 2:07 PM, David Benjamin wrote:
> I think that's right. There's not much benefit to adding 
> supported_versions to a TLS-1.2-only stack. We introduced it in TLS 1.3 
> because of compatibility issues and because it was more flexible and 
> less prone to compatibility issues going forward. The forward-looking 
> benefits don't really apply here (TLS 1.2 has already been updated as 
> TLS 1.3), and TLS 1.2 version intolerance was (painstakingly) cleared 
> out already. (To that end, I'd suggest changing Section 3.1.3 
> of rfc7525bis. The old insecure version fallbacks are no more.)

Already done in our working copy... :-)

https://github.com/yaronf/I-D/pull/258/files

> There's nothing /wrong/ with implementing supported_versions in TLS 1.2. 
> It's, in fact, one of the steps in implementing TLS 1.3. It's just not 
> very useful beyond that. Thus, in a document of recommendations for TLS 
> 1.2 operators, there's no need to include it. (Note the absence of a 
> recommendation doesn't mean we recommend against it.)

Agreed.

On the bright side, just think: eventually we'll publish 7525ter and it 
won't need to talk about TLS 1.2 at all!

Peter