Re: [TLS] Working Group Last Call for draft-ietf-tls-sslv3-diediedie-00

[[e-mail] (Martin Rex)]

Kurt Roeckx wrote:
> Peter Gutmann wrote:
>>
>> There's an awful lot of stuff outside of the browser world that can
>> move to 1.1 if it isn't there already,

The differences between TLSv1.0 and TLSv1.1 are marginal, and when
TLSv1.0 is used with 1/(n-1) record splitting, they provide essentially
the same security -- but TLSv1.1 is *MUCH* less interoperable.


That's not quite true.  There es little, if any stuff outside of the
browser world that could go to > extension-less TLSv1.0, because there
are still too many servers out there that will abort the handshake
when extensions are present or when the version is > TLSv1.0.

Adding insecure reconnect fallbacks, aka "downgrade dance" to each and
every application caller is a complete non-starter.

If there was a standardized fashion how to upgrade from an
extensionless TLSv1.0 ClientHello to an extension-bloated TLSv1.2
ClientHello that works in-band and is completely transparent to the
application caller, then I would gladly add this to both, our
clients and our servers.



>> but that's going to take a long, long time to move to 1.2 if it ever does.
>> Killing 1.0 (which is really just SSL IETF-ised) is a pretty straightforward
>> step if you're already getting rid of SSL because it has most of the same
>> problems, but deprecating 1.1 is going a bit too far.
> 
> TLS 1.1 and 1.2 have only seen widespread adoption recently
> because the major libraries only implemented it recently.  For
> some reason 1.2 actually seems to better support than 1.1.  There
> are a strange set of servers out there that support 1.0 and 1.2
> but not 1.1.

Yes, I've seen those servers.  One of them is:

https://www.portaldasfinancas.gov.pt/

>From what I've been told, they're using an SSL accellerator.  Might be A10.
Will negotiate TLSv1.2 or TLSv1.0, but not TLSv1.1.

They run a few WebServices on related servers with similar configuration
for a legally required data exchange with the portuguese tax authorities.


-Martin