Re: [TLS] AES-CCM ECC Cipher Suites for TLS @ IETF 78

[David McGrew <[e-mail]>]

Hi Nikos,

On Jul 20, 2010, at 2:15 PM, Nikos Mavrogiannopoulos wrote:

> David McGrew wrote:
>
>>> And, IMO, every implementation should
>>> support the un-truncated form, so it should be impossible for the
>>> client to
>>> offer the truncated forms without also offering the un-truncated  
>>> form.
>>> Specifying the truncation in an extension that the server is free to
>>> ignore
>>> would provide for that.
>>
>> I respectfully disagree.  Users of low-power radio devices have  
>> already
>> decided that it is acceptable to use 8 octets or fewer for
>> authentication, and IMO TLS should accept and incorporate that  
>> policy.
>> (802.15.4 link crypto allows zero to 8 octets of authentication  
>> strength.)
>
> Different fields of technology have different needs. Could you  
> elaborate
> on why TLS should accept and incorporate the policy for low-power  
> radio
> devices? Will low-power radio devices use TLS to communicate?

yes, that is the plan of record.   SE2.0 is IP-based (see http://www.zigbee.org/Markets/ZigBeeSmartEnergy/Version20Documents.aspx) 
  and has voted to use TLS to protect communication above the link  
layer, though TLS ciphers and options need to be carefully considered  
in order to be suitable for the constrained environment.   This is a  
very positive thing.  Instead of inventing a completely new protocol,  
or creating a non-interoperable variant (like WTLS), the low-power  
wireless community is looking at ways of using standard TLS.

regards,

David



>
>
> regards,
> Nikos