Subject: Re: [TLS] Working Group Last Call for draft-ietf-tls-downgrade-scsv-00
From: Nikos Mavrogiannopoulos <[email-masked]>
To: "Salz, Rich" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Date: Wed, 15 Oct 2014 14:54:24 +0200
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>

On Wed, 2014-10-15 at 08:19 -0400, Salz, Rich wrote:
> > Can you quantify that tradeoff? How many devices are there really out there
> > that would break? I'd like to have this discussions with hard numbers.
> 
> We (Akamai) see less than 1% SSLv2 and SSLv3 traffic globally and it's concentrated to a few particular clients.  Those clients are important to some customers. They want modern browsers to be protected, by not falling back to SSLv3, but they don't want to cut off those legacy clients.  SCSV fallback solves that problem. It also will solve a problem when some browsers try to use TLS 1.3 but servers haven't been updated.
> Does that help? 

No, it is irrelevant. What matters for this decision are how many TLS
negotiation intolerant servers are out there.

regards,
Nikos