Subject: [Uta] TLS BCP does not recommend TLS extensions

From: Trevor Freeman <[email-masked]>
Date: Thu, 19 Jun 2014 21:24:34 +0000

The TLS BCP does not specify any TLS extensions and it must do so to be a BCP.

If you are implementing any of the EC cipher suites then the elliptic_curves and ec_point_formats extensions would be a MUST support

SNI really should be a MUST support.

renegotiation_info another MUST support

SessionTicket TLS is a SHOULD support.

Trevor

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From: Martin Thomson <[email-masked]>
Date: Thu, 19 Jun 2014 15:49:05 -0700

> SessionTicket TLS is a SHOULD support.

I think that if you say anything about the SessionTicket extension it
should be a little more nuanced than that.  Implementing this on a
server where there are multiple instances serving the same name
requires key synchronization between instances, for example.

The other extensions seem obvious enough.

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From: Yaron Sheffer <[email-masked]>
Date: Sat, 21 Jun 2014 13:56:47 +0300

Hi Trevor,

On 06/20/2014 12:24 AM, Trevor Freeman wrote:
> If you are implementing any of the EC cipher suites then the
> elliptic_curves and ec_point_formats extensions would be a MUST support

RFC 4492 specifies the MUST/SHOULD status for these extensions. I don't 
think we should be repeating or overriding that.
> SNI really should be a MUST support.

I'm all in favor of using SNI. But as far as the draft goes, I believe 
this is an operational decision, and so we should not include such a 
recommendation.

> renegotiation_info another MUST support

Agree.
> SessionTicket TLS is a SHOULD support.

Session resumption is an implementation choice: a server can elect to 
use stateful or stateless resumption, or to not do it at all. We only 
discuss its effect on security.

Thanks,
	Yaron