Privacy tools: Mask your location

Privacy tools: Mask your location

A person’s location can be hugely revealing. Here are some tips on how to mask the information your computer and phone transmit automatically.

By Julia Angwin From ProPublica

Location is one of the most revealing pieces of information about us.

In 2013, researchers found that four instances of a person’s location at a given point in time were enough to uniquely identify 95 percent of the individuals they examined. “Human mobility traces are highly unique,” the researchers wrote. “Mobility data is among the most sensitive data currently being collected.”

Location is also predictive. In another study, researchers at Microsoft were able to use location data to predict where people would be in the future. Wednesdays were the easiest to predict, and weekends the hardest. “While your location in the distant future is in general highly independent of your recent location,” the re-searchers wrote, “it is likely to be a good predictor of your location exactly one week from now.”

To mask my location I took several steps:

1) When browsing the Web, I tried to use the Tor Browser as often as possible. Tor anonymizes the location — known as the IP Address — that your computer transmits automatically to every website you visit. It’s amazing to see how revealing your IP address can be — this site pinpoints my location exactly.

Tor bounces your Internet traffic around the world so that your computer’s location is masked. However, because your traffic is bouncing around the world, using Tor can slow down your Web browsing.

2) Masking my location when using my cellphone was more difficult. I turned off ‘location services’ for my apps. And I tried to opt out from companies that track cellphone users via the Wi-Fi signal emitted by their phone.

I identified 58 companies that appeared to be in the mobile location tracking business — ranging from advertisers to wireless carriers. Of those, only 11 offered opt-outs — which I attempted to complete. Here is the chart of the folks I found that offered opt outs.

Service Type Privacy Policy Opt Out Link Information Required

DataXu Advertising Link Link Cookie

Drawbridge Advertising Link Link Cookie

Sense Networks Advertising Link Link Device ID

Euclid Analytics Analytics Link Link MAC address

Flurry Analytics Link Link Device ID and UDID

Mixpanel Analytics Link Link Cookie

Nomi Analytics Link Link MAC address

AT&T Wireless Link Link via your AT&T account

Sprint Wireless Link Link Via your Sprint account

Verizon Wireless Wireless Link Link via your Verizon a-ccount

T-Mobile Wireless Link Link Cookie

The Future of Privacy Forum has also built a location opt-out site, which as of today, offers opt-outs from 11 location tracking companies.

Ultimately, I decided that turning off my Wi-Fi signal was a more effective opt-out.

3) When I really do not want my location to be tracked, I throw my phone into a Faraday cage — a bag that blocks it from transmitting signals to Wi-Fi or the cellphone tower. I use this one from Off Pocket, but any Faraday cage will do.

Of course, this also means that I can’t use my phone. So, like most of my privacy fixes, it is a highly imperfect solution.