iOS/Android: If you're worried about apps tracking your location, it's not enough to limit your location sharing. You need to limit camera-roll sharing too. If you've ever given an app access to your camera roll - to take photos, or store screenshots, or any given reason - you've also let it see where all those photos were taken. Felix Krause, an iOS developer and security writer, built an app to demonstrate this back door.
The recent publication of a leaked video demonstrating American security firm Raytheon's social media mining tool RIOT (Rapid Information Overlay Technology) has rightly incensed individuals and online privacy groups. In a nutshell, RIOT -- already shared with US government and industry as part of a joint research and development effort in 2010 -- uses social media traces to profile people's activities, map their contacts, and predict their future activities. Yet the most surprising thing isn't how RIOT works, but that the information it mines is what we've each already shared publicly.
The EXIF data stored with photographs can be useful if you want to replicate the same settings on your camera, but it can also reveal information you'd rather keep private. If you want to remove all EXIF data from photos before uploading them, ExifPeeler is a bare-bones web site that will get the job done.
Windows only: Setting (and re-setting, and re-setting) your camera's clock can be a pain, but wildly incorrect photo timestamps even more so. Here's a free program that can keep your shots in sync.
Windows only: JPEG & PNG Stripper an extremely small portable application that strips the metadata out of JPEG and PNG image files. Why would you want to strip down an image file? Ask former TechTV host Cat Schwartz, who in 2003 received a rather embarrassing lesson in the power of metadata. In short, a cropped headshot posted on her blog contained an embedded, full-pic thumbnail with, well, a lot more than just a head and shoulders. Even if you're not cropping your mug out of a nude composition, there are others reasons you'd want to remove the metadata from an image. All sorts of information—like exposure time, aperture settings, camera used, and GPS coordinates—can potentially be embedded into an image. JPEG & PNG Stripper removes every bit of metadata, leaving just the unaltered image behind. Whatever your motivation for sanitising your image, you'll know that only the image itself remains. The screenshot at right shows a read of some of the metadata for an image I scrubbed in testing and, as promised, the application ripped all the metadata out without altering the appearance of the image itself. JPEG & PNG Stripper is freeware, Windows only.
