Re: [TLS] TLS1.2 vs TLS1.0

Hi Ulrich

IMO mandate TLS 1.2 (as SEP2 did).

For all of the reasons you mentioned below.

With OpenADR, we are talking about an app that impacts the electric grid.

Cheers

On 5/20/2013 4:47 PM, Ulrich Herberg wrote:
> Hi,
>
> I have not followed this WG, so please forgive me if a similar
> question has already been discussed.
>
> I am participating in another SDO on a standard for automated Demand
> Response, called OpenADR (www.openadr.org), an application for the
> smart grid. The application is basically a web service, exchanging XML
> over HTTP over public networks, and using TLS (with RSA and ECDSA /
> SHA1 ciphers for TLS 1.0 and SHA2 for TLS1.2). Currently, the draft
> allows for TLS1.0 and 1.1, but recommends using 1.2 (and requires
> vendors to provide a migration plan in case TLS1.0 is obsoleted) .
> TLS1.0 and 1.1 RFCs have been obsoleted by the IETF; but I am not sure
> about the best current practice. Is it absolutely discouraged to use
> them? The argument in the OpenADR alliance is that many libraries and
> programming languages do not support TLS1.2, so they recommend to
> start the handshake with 1.2 and then downgrade - if required - to
> 1.0. I read that NIST disallows SHA1 after 2013; which would also
> affect TLS1.0, which does not support SHA2.
>
> What would be your recommendation in this case? Mandate TLS1.2 and
> disallow TLS1.0? Or just strongly recommend ("SHOULD") to use TLS1.2
> and SHA2 ciphers, and otherwise to use TLS1.0?
>
> Best regards
> Ulrich
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