MAC addresses will be used to reveal where you live

Conor has responded to my comments on why house numbers don't make a good metaphor for MAC addresses.

He writes that when I characterized house number as a “universal identifier”,

[Kim's argument] “confuses house address with house number. A house number is not able to be used as a universal identifier (I presume that there are many houses out there with the number 15, even in the same town, many times even on the same street in the same zip code (where the only difference is the N.W. and S.E. on the end of the street name).

“Like SSIDs and MAC addresses, the house number is only usable as an identifier once you get to the neighborhood and very often only once you get to the street.”

I like Conor's distinction between house number and house address.  It's true there are many houses with the number 15, thus the house number is a local identiier, and only becomes universal when combined with the street name, the city, and so on.  I hadn't understood that this is what he was trying to say.

Then Conor continues:

“I will admit that there are some differences with the MAC address because of how basic Ethernet networking was designed. The MAC address is designed to be unique (though, those in networking know that this isn't always the case and in fact most devices let you override the mac address anytime you want). So this could be claimed to be some form of a universal identifier. However, it's not at all usable outside of the local neighborhood. There is no way for me to talk to a particular MAC address unless I am locally on the same network with that device.”

Conor is completely right here.  In networking as we have known it, the MAC address is not usable outside the “local network neighborhood”.  But that is exactly what this WiFi snooping is about to change.  In fact this is very much the core of what I'm talking about.

MAC addresses will be used to reveal where you live

Once you have snooped peoples’ MAC addresses, and put them into a database linking them to “where they live” (literally),  you have dramatically changed the way network identifiers work.

In this new world, armed with such a database, if you see a MAC address somewhere – anywhere – you can look it up in your database – precisely because it is unique – and see where “it lives”.   When I say, “where it lives”, I don't mean what network it belongs to.  I mean where it is normally located in physical space – as a street address.  

Is there some way to opt out of this?  No – other than turning everything off.  Unfortunately, given the way networks are designed, we have no choice but to reveal our MAC address when we use our Wireless.  So  anyone who is physically near us and has access to a linking database has access to where we live. I'll explore the implications of this going forward.

Conor concludes,

“I do believe that a more privacy enabled design of networking would have allowed for scenarios where MAC addresses were more dynamic and thus reducing the universal-ness and persistence of the MAC address itself…”

We both agree on this.  And IPV6 has plenty of options that could make this possible.  However, the current infrastructure is the one we live in, and one which is sorely in need of protections, mores and regulations.  The fact that current technology allows the creation of Dr. No technology like that which Google StreetView WiFi has laid on the world doesn't mean that society should or will.



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Kim Cameron

Work on identity.