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[STDS-802-11-TGBH] ID encoding

Hi Jouni,

Thanks for your presentation 22/2013r1. have the following comments:

 

  1. Unclear who allocates the ID.  Does non-AP STA allocate or AP, or both?
    1. If both advertise support and non-A STA does not include ID IE  in request, does AP include ID IE in the response?
    2. Can non-AP STA allocate?  If non-AP STA includes a “not recognized” ID IE we are back to the discussions that have plagued Device ID.
  2. Then, how is ID changed?  Presumably it needs an ID IE from the AP or does the non-AP STA control?
  3. If the IE is not encrypted then there is no difference to the MAAD scheme except  I can’t see any advantage in adding an IE which acts as an identifier.  In fact, this could be construed as a fingerprint for this STA.  In MAAD the MAC address appears random even though identifiable by one AP. The mere presence of the ID IE clearly sets the non-AP STA apart. 
    1. Non-AP STA could I suppose include a dummy ID each time, as if not, it identifies clearly which APs it is interested in, encrypted or not.
  4. Encrypting the ID means that the STAs need to store the ID and the key for each connection, plus the need to carry out the computations each time , plus noting the timestamp from the beacon, assuming that it can get the request on the air before the next beacon. But, need to ask for what purpose encrypt?
    1. In TGbi I had a lot of push back on the ‘paparazzi attack’ with what appeared to be a general view that protection to this was not needed. If so, then MAAD works fine as is and the idea that somehow an attacker copies the MAC address and then uses it to ‘fool’ an AP is moot.  In fact, as I have pointed out numerous times, “so what”, even if this does happen, the bandit can’t associate anyway so why waste time adding computations and complexity? 
    2.  So, what “replay  frames” or “cloning” problem is the need to encrypt addressing?   In practice it is not a problem (can’t associate anyway, and it seems that this attack is not of interest anyhow) and hence does not merit adding computational complexity.

 

Will this scheme work – yes

May this be of interest to TGbi - maybe

Does it have any real advantage over MAAD in the TGbh context – No

If this ID IE is only included when addressing an AP to which it wishes to be pre-identified, then it is an obvious giveaway.  With MAAD, for example, there is nothing to show that this AP is special. 

 

Finally I would like to note that TGbh is looking for easy to implement solutions to quickly address the Use Cases broken by RCM.   How quick and easy to implement is this scheme compared to MAAD?  - for me, MAAD wins easily and is a TGbh solution.   

 

Thanks

Graham

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