Re: [Dtls-iot] DTLS multicast security

On 9/19/2014 11:44 AM, Carsten Bormann wrote:
> On 19 Sep 2014, at 17:01, Michael StJohns <msj@nthpermutation.com> wrote:
>
>>> I agree with Ludwig that having a secure multicast is considered a benefit by many.
>> My problem with this statement is that I would consider anti-gravity to be a benefit to many, but that AG has exactly the same scientific basis as symmetric key multicast security - none.  There's long, long experience on this topic that the document writers have ignored.
> This discussion is a great demonstration that the IETF is unfit to do appropriate security.
>
> Yes, there is no known way to do efficient multicast security at military security levels*).
>
> I’m not interested in military security.
> The use cases I’m interested in need neither nonrepudiation nor do they need to address a threat model that involves tampering with devices.
>
> draft-mglt-dice-ipsec-for-application-payload demonstrates that we already have the IETF protocols in place to do appropriate security here.
>
> All the various Philips proposals tried to do was to package this functionality in a way that fits better to the other security protocols that DICE is trying to improve.  (And, yes, that work wasn’t finished before it was derailed.)
>
> If we cannot continue this work because it wouldn’t solve other use cases we don’t care about, that would be rather disappointing.
>
> Grüße, Carsten
>
> *) TESLA is not solving our problem either.
>
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Carsten - if we could constrain the use of whatever we came up with to a 
group of 10-12 lightbulbs inside someone's home, I'd say go ahead.  But 
this will end up as a general IOT cyber-physical control protocol.  It 
*will* be used on other things and it will be hacked.   Those are my 
assumptions - they may be wrong, but they are the most responsible 
assumptions to make when considering the protocol design.    This isn't 
military security, but it is security necessary when the internet 
impinges on and controls the physical world.

Later, Mike