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. 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.

Sam

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