iOS 8 to thwart Wifi tracking

Apple have recently announced the latest version of their mobile operating system, iOS 8, including changes which might affect tracking systems used in supermarkets and shopping centres.

In the last few years a number of companies have sprung up with the offer of tracking customers for the benefit of analytics. Asda are doing this in the UK, as are shopping centres and plenty of US companies.

What is wifi tracking?

The basic principle is that your smartphone is constantly looking for wifi networks to connect to and – in doing so – sends out a unique identifier (a “MAC address”) which can be used to trace you. With enough network access points it becomes possible to work out where somebody is, based on which points their phone tries to connect to.

The outcome of this data is pretty beneficial for shop owners, estate managers and so on. It tells them how people move around their stores, which areas are hot-spots and which others might be ideal places for promotions.

Apple’s announcement is short on detail, but it appears that they are preparing to scramble the MAC address when the phone tries to search for wifi signal, making it more difficult to track movements between one place and another. The key is how often they do this – if the MAC address is scrambled once a day (for example) the drawbacks will only be for long-term tracking, i.e. watching for repeat visits. If it changes every few seconds the entire capability is gone.

Arguably wifi tracking is an opportunistic service anyway, making use of an artefact of technology that was never designed for tracking purposes. Its utility, however, has been enormous and companies will certainly miss this data if it goes.


Are Apple doing this for privacy’s sake? It would seem so. In the right hands, Wifi tracking is anonymous. Try hard enough and – in the right circumstances – it becomes possible to identify people. Most companies won’t try to do this for fear of running foul of data protection laws, but that won’t stop everybody.

In any case, this won’t prevent opt-in tracking such as the Asda scheme mentioned earlier. The offer of free wifi comes with strings attached – they can track and identify you, and once connected to a ‘known’ wifi hotspot your phone will no longer scramble its MAC address, giving the company full access to your individual movements.

Direct selling need not be an option either – shops and districts offering free wifi can still benefit from tracking, but this will likely be forced into terms and conditions. Whether they use that to gather personal information and market to individuals is entirely a question for them and their visitors (the latter always has the option to decline the invitation).

That might see the opening of more free wifi hotspots, as companies will need to offer this to retain the all-important MAC address. I’m not sure if Apple see things this way as well, but it’s certainly an interesting possibility.