[LINK] itNews: 'Wi-fi router owners get Google location opt-out'

Roger Clarke Roger.Clarke at xamax.com.au
Wed Nov 16 07:41:18 AEDT 2011

Wi-fi router owners get Google location opt-out
Liam Tung
Nov 16, 2011 6:47 AM (50 minutes ago)

But why not opt-in?

Wireless router owners that do not want Google to use their devices 
to improve its mobile location services can now opt out. 

To opt-out, wireless access point owners must add "_nomap" to the 
tail of the an Service Set Identifier (SSID) -- a network's existing 
name. So, for example, "HomeNetwork" would be renamed to 

Google's location database, Google Location Server, collects SSID and 
unique device IDs known as a MAC address to improve its location 
services, such as mapping or apps that rely on location information 
generated by access points instead of GPS.  

In September Google said it would make the feature available globally 
so that once a user opted out, it would "not use that access point to 
determine users' locations". 

Google's global privacy counsel Peter Fleisher said Tuesday that it 
was "introducing a method that lets you opt out of having your 
wireless access point included in the Google Location Server."

Once a user has opted out, Google explains on its support page that 
"the next time a user's device sends information about your wi-fi 
access point to the Google Location Server through a reliable channel 
[such as an Android device], our system will note the _nomap tag and 
remove the access point from our Location Server after it is 

The new option appears to fall in line with a Dutch Data Protection 
Authority ruling in August this year that "obliged [Google] to offer 
users the option to opt-out, so they can effectively object to the 
processing of data on their wi-fi routers at all times and free of 

Tuesday's changes appeared to ste from the Dutch authority's 2010 
investigations into Google StreetView car's collection of wi-fi data, 
which noted that "MAC addresses combined with a calculated location 
are personal data because the data can provide information about the 
wi-fi router's owner."

While Google positioned the opt-out method as preferable, in order to 
"protect against others opting out your access point without your 
permission", others have criticised it for not making the system 

"Google should go opt in like Facebook! Should be SSID_mapme," 
Veracode CTO & co-founder Chris Wysopal responded on Twitter.

"So SSID_nomap can now immediately be used to profile people who set 
it. Just adding _nomap is a privacy fail in itself," security 
researcher Nick DePetrillo pointed out. 

And since Google still collects MAC addresses, security and privacy 
researcher, Christopher Soghoian, wanted Google to explain how they 
were stored. 

"Dear Google: How do you store the MAC addresses of wi-fi routers 
that don't want to be mapped? Raw addresses, hash them, or a bloom 
filter?," Soghoian asked. 

Renaming an SSID will only be observed by Google from Tuesday, 
however Fleisher said it hoped that over time the "_no map" string 
will be adopted universally.

Roger Clarke                                 http://www.rogerclarke.com/
Xamax Consultancy Pty Ltd      78 Sidaway St, Chapman ACT 2611 AUSTRALIA
                    Tel: +61 2 6288 1472, and 6288 6916
mailto:Roger.Clarke at xamax.com.au                http://www.xamax.com.au/

Visiting Professor in the Cyberspace Law & Policy Centre      Uni of NSW
Visiting Professor in Computer Science    Australian National University

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