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OPLIN 4cast #349: Telltale MACs

Posted in 4cast

radarModern smartphones contain quite a few sensors that apps can use to gather data about you. The tri-axial accelerometer, for example, can be used by exercise apps to determine how fast you are moving while your phone is in your pocket or purse, and when coupled with data gathered by the phone’s magnetometer and gyroscope, the apps can also know in what direction you are moving and even gather clues about how much you weigh. Of course, if you don’t use the apps, then you don’t share this data about yourself. But there’s one piece of information a smartphone broadcasts every time it is using Wi-Fi or Bluetooth that you can’t turn off: its MAC (media access control) address, which is a hardware identification number required by most network technologies. A marketing company in London recently demonstrated a clever way of harvesting useful information from MAC addresses – until public outcry forced city officials to make them turn it off.

  • This recycling bin is following you (Quartz/Siraj Datoo)  “The bins record a unique identification number, known as a MAC address, for any nearby phones and other devices that have Wi-Fi turned on. That allows Renew to identify if the person walking by is the same one from yesterday, even her specific route down the street and how fast she is walking.”
  • No, this isn’t a scene from Minority Report. This trash can is stalking you (Ars Technica/Dan Goodin)  “The marketing materials don’t say this, but it might also be possible to attach specific attributes to the MAC addresses that are collected. A phone that goes into the women’s room probably belongs to a female, for instance, while a MAC address entering the Big and Tall clothing retailer probably belongs to a person of large carriage.”
  • Smartphone tracking: When good intentions go wrong (ScreenMedia Daily/SMD Editor)  “Renew didn’t do itself any favors when they said in their press release that the ‘consolidated data of our beta testing highlights the significance of the Renew ORB technology as a powerful tool for corporate clients and retailers. It provides an unparalleled insight into the past behavior of each unique device including entry/exit points, dwell times, places of work, places of interest, and affinity to other devices – and should provide compelling reach database for predictive analytics, such as likely places to eat, drink, personal habits etc.’”
  • City of London calls halt to smartphone tracking bins (BBC News/Joe Miller)  “While the collection of anonymous data through MAC addresses is legal in the UK, the practice has been described as a ‘grey area’. The UK and the EU have strict laws about mining personal data using cookies, which involves effectively installing a small monitoring device on people’s phones or computers, but the process of tracking MAC codes leaves no trace on individuals’ handsets.”

MAC fact: The first portion of the MAC address, which is stored in a smartphone’s hardware when it is made, identifies the manufacturer, so the recycling bins in London also knew the brands of the phones people were carrying.