In recent years, in connection with a massive expansion of the number of fake profiles on social networks environment, the need to look for methods that allow you to distinguish the fake from the real information has been increasing. One of the methods to identify false photo from the "modified one" or even "fake one" is the use of EXIF metadata specification.
What is EXIF?
EXIF (exchangeable image file format) is the information that is contained in digital photos (and other file formats, such as audio format RIFF/WAV), which is generated automatically just by the device that took the photo. For example, by using EXIF you can distinguish whether the photo was taken with a digital camera or mobile phone, whether it was modified in Photoshop, for instance, when the photo was taken and also the place where it was taken (using GPS location).
EXIF can then be used for example in a situation where an unknown Internet user sends you a photo and he/she claims that it was just taken to prove you his/her identity. Using free available Internet sources that can load and view EXIF, you can easily recognize whether the user really sent you an unedited photo, if the photo was edited, in which program, etc. The problem arises in a situation when you try to edit the photo (make smaller, enlarge, retouch). Many video editors are not set to save EXIF data and when saving a modified photo, the editors do not save the data. Therefore, it is always necessary to work with the original photo, not the reduced or otherwise modified one.
Where you can try EXIF?
For those who prefer a desktop application, I can recommend the program PIE - Picture Information Extractor (www.picmeta.com), which contains a very detailed view of the metadata contained in the photo. A suitable alternative may then be, for example, Exif Reader. For those who prefer online tools, I recommend http://regex.info/exif.cgi that can show how to display metadata and how to use Google Maps to target location where the image was created.
Examples for verification
I have tried EXIF on iPhone 4S, iPhone 5, iPad 2 and HTC Desire, in all cases; the original photo included a detailed metadata including GPS location. In order to verify loading metadata, I attach photos with different EXIF records, where you can try to detect, for example, the geographical location in which the photo was taken.
In the photo of a woman we can see that it was taken at coordinates 55 ° 4 '51 "N, 82 ° 57' 55" E (Russia, Novosibirsk), the second picture was taken at coordinates 40 ° 44 '22 "N, 73 ° 59' 23 "W (New York, USA).
dr. Kamil Kopecký, E-Bezpečí
Sources:
Specifikace EXIF: http://cs.wikipedia.org/wiki/Exif
