Manipulating stored geocoordinates in cellphone photos

Programming Snapshot – Go Geofuzzer

Article from Issue 240/2020

Mike Schilli loves his privacy. That's why he's created a Go program that adds a geo-obfuscation layer to cellphone photos before they are published on online platforms to prevent inquisitive minds from inferring the location.

If you sell your stuff online, you might overlook the potential risk of sales-promoting cellphone photos revealing highly sensitive private information. When you take a picture of the goods at home with your cellphone, the image file may also contain the geodata with which the private address can be determined to within a few yards. Large sales platforms generally do not publish this meta-information, but who wants to give away more information than is absolutely necessary on Ebay or Facebook?

The cellphone also erases geodata directly if desired – but then it looks as if the user has something to hide. That's why the self-written Go program in this issue adds a geo-obfuscation layer to image files to make sure that the geocoordinates are randomly blurred. From this, it might be possible to determine the seller's location down to the neighborhood, but not the exact address.


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