In HART, you join with EUI-64, and all transport sessions use that.
The network manager assigns and knows the mapping from two-byte
short address to EUI-64.
For the MIC at L2 your neighbors don't know or care what your real name is.
They just use the two byte (unique for this network) short address.
If the manager were to assign duplicate short addresses, then two or more
packets sent in the same ASN from the same short address would have the
same nonce and L2 MIC key, which is not good policy but leaks exactly
nothing.
It seems like saying something along the lines of "don't use short
addresses in
nonce construction if there is a chance that short addresses will be
duplicated
with the same key" would be an appropriate warning to see in -2015.
ksjp
On 4/11/2015 4:37 PM, Michael Richardson wrote:
Tero Kivinen <[email protected]> wrote:
>> The reality is that I'm trying to make sure that we have a secure MIC
>> that doesn't require that layer-2 neighbors know each others EUI-64.
>> All that they need to know is the two-byte short address.
> The 802.15.4-2011 do require you to know your neighbors EUI-64
> already. Even if you use short address in the nonce, you still need to
> fill in the DeviceDescriptor and for your neighbors and for that you
> need to know the extended address of it. You do not need to know the
> short address, that can be left as 0xffff if you do not know it.
So, you don't need to use the EUI-64, but you do need to have a mapping of
short-address to EUI-64. How does such a mapping become known?
How can any of this work in the field today?
--
Michael Richardson <[email protected]>, Sandelman Software Works
-= IPv6 IoT consulting =-
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