Friday, April 8, 2011

Location privacy: shared photos know where you are (were)

Who knew before Facebook, Flickr and similar just how widely people wanted to share photos of what a great time they're having?

You can opt out of Facebook Places (for now); you don't have to sign up to Foursquare, Gowalla or turn on the geo-location of your Tweets. Last month's news was of a German politician's movements tracked through his cell phone. The map was only produced after he got the data from his mobile phone service provider, hardly something most of us can do.

But every photo you take on a smartphone and publish with services like Twitpic or Yfrog or Facebook has the location of the photo stored as part of the image data. Your locations are out there, for others to discover.

An individual Tweet or a single photo or 'check-in' doesn't reveal much; but try viewing your Foursquare travel history on a 'heat map.' Or learn about an app suitably called 'Creepy.' These tools will reveal clusters of your presence around home, workplace and the spots you hang out - Do you go to the gym, or church, or a bar at the same time each week? These apps know it. And they show where you were, when, maybe where you are now, and (because most of us live fairly routine lives) people looking on can make a fair guess about where'll you'll be in the future.

It occurred to me as I 'checked in' to a certain city that people viewing my history could make a great guess about the organisation I was meeting with and the sales relationship I was hoping to form!

Why build 'Creepy?' There's a great interview with the developer at thinq. He says he did it,
"First, to try and raise awareness about privacy in social networking platforms. I wanted to stress how 'easy' it is to aggregate all the seemingly small and innocent pieces of data people are sharing into a 'larger picture' that potentially gives away information that users wouldn't think of sharing. For example, where do they live, where do they work, where and at what times they are hanging out, when they are not at home et cetera. I think that sometimes it is worth 'scaring' people into being more careful on how much they share online.

"Secondly, I wanted to create a tool for social engineers to help with information gathering. I believe Creepy can be of real use to security analysts performing penetration testing for the initial process of gathering information about the 'targets' - information that can be used later for a number of purposes."

I'm not sure I understand what he means by his second reason, but to the extent I do it succeeds in scaring me!
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