Tube passengers tracked by phone WiFi
 

In message , at 14:16:05
on Sun, 10 Sep 2017, remarked:
In article , (Roland Perry)
wrote:

In message , at
13:49:16 on Sat, 9 Sep 2017, remarked:

Apart from anything else, this is about wifi coverage which is for data
which is little used for voice calls.

Never used Whats App voice calls, grandad?

No, nor Skype on my mobile, as it happens. Do you know the volumes?

https://blog.whatsapp.com/10000625/W...g-100-million-
conversations-every-day

I did say little used not unused.

Every little helps [tm].

I've taken to using Whats-App voice when the person I'm calling is in a
GSM not-spot, but has wifi coverage.
--
Roland Perry

Tube passengers tracked by phone WiFi
 

On 2017-09-09 09:47:23 +0000, Graeme Wall said:

On 09/09/2017 10:37, Someone Somewhere wrote:
On 08/09/2017 17:34, Sam Wilson wrote:
On 2017-09-08 14:40:46 +0000, Martin Coffee said:

On 08/09/17 15:00, Sam Wilson wrote:
On 2017-09-08 13:18:33 +0000, Martin Coffee said:

On 08/09/17 14:03, Recliner wrote:
[snip]
[TfL] said it was talking to the Information Commissioner’s Office about its
plans and passengers could opt out by switching their wifi off. It said
that the phone data was “de-personalised�, with nothing to identify
individuals.

The system works by using 1,070 wifi access points on the Tube network.
They pick up on a code that identifies each phone, the media access control
(MAC) address, and track them from point to point.

Each MAC address was “irreversibly� encrypted, TfL said. Prior to
encryption, a random code is added to each to ensure that the phone cannot
be identified even if the encryption could be reversed. No browsing data
was collected, meaning that emails and the internet habits of passengers
could not be shared with third parties.
[snip]
Let's face it.Â* Even if encrypted, you cannot anonymise a MAC address
as it is unique to each phone.

You can turn it into something that can't be (realistically) turned
back into a MAC address that can be used to identify the
phone/tablet/laptop/whatever.

You don't have to turn the "anonymised" back to a MAC address to
de-anonymise the data.Â* You just encrypt a MAC address and identify the
location data in just the same manner as the tracking occurs. Thus the
location can still be re-associated with the original MAC address.

Sure, if you know a particular MAC address and the encryption procedure
and access to the location data then you may be able (and I note Dr B's
comments in his response) to recreate the key and therefore track the
MAC address.Â* Most of us (and I again I bow to Dr B) probably can't do
that.

Surely the most likely people to want to do this would be criminals
anyway, so criminalising their activities seems slightly pointless.
Deterring casual peepers is probably worth doing.

Surely the problem is if this becomes widespread as eventually you'll
get enough data to identify not just the phone but the individual.

It's fine if it's kept to the tube,Â* but let's take the advertising
angle,Â* presumably the advertisers won't be satisfied with just knowing
what the busiest platform is but would prefer to target their adverts
to one or more groups of people on that platform.

By hooking up a similar system with retailers they work out that of the
group on the platform at 08:30 a significant proportion are e.g.
Waitrose shoppers.Â* And it then goes on and on until you end up pretty
much being able to identify the iindividual, what they buy, where they
live etc without actually ever using any personally identifiable
information.

I'm not sure of the relevant legislation but presumably the only way to
avoid this is that each entity having such a system has to have a
different algorithm (or at least key) for anonymising the MAC data so
each data set remains siloised (but would the supplier of the system
still be able to join the different datasets?)


Shopping malls have been doing a similar thing to send you "targetted
adverts" as you approach various shops.

Hello Mr Yakamoto, welcome back to GAP...

Sam

--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Tube passengers tracked by phone WiFi
 

On Sun, 10 Sep 2017 08:27:12 +0100
Someone Somewhere wrote:
On 09/09/2017 19:12, Graeme Wall wrote:
SMS initially.


It can be SMS, it could even be electronic billboards or display
screens. Imagine walking on to a tube platform, to be greeted by a
display with an advert from Boots - "Hey Someone Somewhere - you haven't
bought Preparation H recently. If your arse grapes are still troubling
you, you'll be pleased to know that we currently have 50p off our jumbo
tube" or similar....

Of course there is always the option - possibly heresy for Millenials - to
switch off wifi on your phone. I know, its radical, but it might just work.

--
Spud

Tube passengers tracked by phone WiFi
 

In message , at 13:43:05 on Mon, 11 Sep
2017, d remarked:
It can be SMS, it could even be electronic billboards or display
screens. Imagine walking on to a tube platform, to be greeted by a
display with an advert from Boots - "Hey Someone Somewhere - you haven't
bought Preparation H recently. If your arse grapes are still troubling
you, you'll be pleased to know that we currently have 50p off our jumbo
tube" or similar....

Of course there is always the option - possibly heresy for Millenials - to
switch off wifi on your phone. I know, its radical, but it might just work.

You've raised a *very* interesting point. This survey may be of only
that self-selecting subset of passengers who *do* keep their wifi on [on
the tube].

Does the associated article mention whether they attempted to correct
for this built-in bias?
--
Roland Perry

Tube passengers tracked by phone WiFi
 

On 11/09/2017 14:53, Roland Perry wrote:
In message , at 13:43:05 on Mon, 11 Sep
2017, d remarked:
It can be SMS,Â* it could even be electronic billboards or display
screens.Â* Imagine walking on to a tube platform, to be greeted by a
display with an advert from Boots - "Hey Someone Somewhere - you haven't
bought Preparation H recently.Â* If your arse grapes are still troubling
you, you'll be pleased to know that we currently have 50p off our jumbo
tube" or similar....

Of course there is always the option - possibly heresy for Millenials
- to
switch off wifi on your phone. I know, its radical, but it might just
work.

You've raised a *very* interesting point. This survey may be of only
that self-selecting subset of passengers who *do* keep their wifi on [on
the tube].

Does the associated article mention whether they attempted to correct
for this built-in bias?

Are you presuming that there is a correlation between whether people
keep wifi on and choose particular routes? If we assume they are
independent then TfLs analysis still stands.

Presumably by analysing ticket data we can see what percentage of
passengers are carrying a device with wi-fi enabled (although in my case
that is often 3 or more - before you ask, personal phone, work phone and
kindle)

Tube passengers tracked by phone WiFi
 

On 11/09/2017 14:53, Roland Perry wrote:
In message , at 13:43:05 on Mon, 11 Sep
2017, d remarked:
It can be SMS,Â* it could even be electronic billboards or display
screens.Â* Imagine walking on to a tube platform, to be greeted by a
display with an advert from Boots - "Hey Someone Somewhere - you haven't
bought Preparation H recently.Â* If your arse grapes are still troubling
you, you'll be pleased to know that we currently have 50p off our jumbo
tube" or similar....

Of course there is always the option - possibly heresy for Millenials
- to
switch off wifi on your phone. I know, its radical, but it might just
work.

You've raised a *very* interesting point. This survey may be of only
that self-selecting subset of passengers who *do* keep their wifi on [on
the tube].

Which will be most, how many people actually bother switching it on and off?


Does the associated article mention whether they attempted to correct
for this built-in bias?

In the noise.

--
Graeme Wall
This account not read.

Tube passengers tracked by phone WiFi
 

In message , at 16:46:41 on Mon, 11 Sep
2017, Graeme Wall remarked:

You've raised a *very* interesting point. This survey may be of only
that self-selecting subset of passengers who *do* keep their wifi on
[on the tube].

Which will be most, how many people actually bother switching it on and off?

Who knows? Different demographics perhaps, which is the whole point.

I switch my wifi off whenever out and about because it's too patchy to
warrant the battery consumption.
--
Roland Perry

Tube passengers tracked by phone WiFi
 

In message , at 15:16:32 on Mon, 11 Sep
2017, Someone Somewhere remarked:
On 11/09/2017 14:53, Roland Perry wrote:
In message , at 13:43:05 on Mon, 11 Sep
2017, d remarked:
It can be SMS,* it could even be electronic billboards or display
screens.* Imagine walking on to a tube platform, to be greeted by a
display with an advert from Boots - "Hey Someone Somewhere - you haven't
bought Preparation H recently.* If your arse grapes are still troubling
you, you'll be pleased to know that we currently have 50p off our jumbo
tube" or similar....

Of course there is always the option - possibly heresy for
Millenials - to
switch off wifi on your phone. I know, its radical, but it might
just work.
You've raised a *very* interesting point. This survey may be of only
that self-selecting subset of passengers who *do* keep their wifi on
[on the tube].
Does the associated article mention whether they attempted to
correct for this built-in bias?

Are you presuming that there is a correlation between whether people
keep wifi on and choose particular routes? If we assume they are
independent then TfLs analysis still stands.

Actuall, it's worse than that, because different types of traveller
might have smartphones or not, at all. Older passengers might have fewer
phones/device, and might make decisions based more on step-free or long
term habit, than short term optimisation. Conversely, younger people in
a hurry, with more devices, might bail out to alternative less obvious
routes more impatiently.

Presumably by analysing ticket data

You might be able to make a stab by comparing the number of ticket
barrier entries/exits at a non-interchange station or two, then the
number of unique phones you detect on the platforms.

we can see what percentage of passengers are carrying a device with
wi-fi enabled (although in my case that is often 3 or more - before you
ask, personal phone, work phone and kindle)

Well, that's going to bias the results too, because you'll perhaps show
up as three trips not one. And maybe people with lots of devices are
more prone to be fussy about choosing the quickest route.
--
Roland Perry

Tube passengers tracked by phone WiFi
 

wrote:
On Sun, 10 Sep 2017 08:27:12 +0100
Someone Somewhere wrote:
On 09/09/2017 19:12, Graeme Wall wrote:
SMS initially.


It can be SMS, it could even be electronic billboards or display
screens. Imagine walking on to a tube platform, to be greeted by a
display with an advert from Boots - "Hey Someone Somewhere - you haven't
bought Preparation H recently. If your arse grapes are still troubling
you, you'll be pleased to know that we currently have 50p off our jumbo
tube" or similar....

Of course there is always the option - possibly heresy for Millenials - to
switch off wifi on your phone. I know, its radical, but it might just work.


I usually forget to switch it back on and end up using my 4G allowance at
home...


Anna Noyd-Dryver

Tube passengers tracked by phone WiFi
 

In message , at 04:57:17 on Tue, 12 Sep
2017, Anna Noyd-Dryver remarked:

Of course there is always the option - possibly heresy for Millenials - to
switch off wifi on your phone. I know, its radical, but it might just work.

I usually forget to switch it back on and end up using my 4G allowance at
home...

My Android phone uses wifi in preference to mobile data, when wifi is
available.
--
Roland Perry