Datensätze enthalten nicht nur die eigentlichen Daten, sondern auch Daten über sich selbst. Beispielsweise enthalten Fotos Daten über den Aufnahmeort, das Aufnahmedatum, die getätigten Einstellungen oder den Fotographen.


Bei diesen Informationen über die Daten selbst spricht man von Metadaten.

Metadaten von Fotos erlauben es die Kamera zu identifizieren

Harry Potter and the Deathly Hallows is, as far as anyone knows, the last book in the Harry Potter series. Its arrival was eagerly awaited, with lines of anxious Harry fans stretching around the block at bookstores everywhere. One fan got a prerelease copy, painstakingly photographed every page, and posted the entire book online before the official release. A labor of love, no doubt, but a blatant copyright violation as well. He doubtless figured he was just posting the pixels, which could not be traced back to him. If that was his presumption, he was wrong. His digital fingerprints were all over the images.

Digital cameras encode metadata along with the image. This data, known as the Exchangeable Image File Format (EXIF), includes camera settings (shutter speed, aperture, compression, make, model, orientation), date and time, and, in the case of our Harry Potter fan, the make, model, and serial number of his camera (a Canon Rebel 350D, serial number 560151117). If he registered his camera, bought it with a credit card, or sent it in for service, his identity could be known as well. (Abelson et al., 2008; S. 24.)

Metadaten eines Worddokuments in Form von Textänderungen verraten Geheimnisse

In October, 2005, UN prosecutor Detlev Mehlis released to the media a report on the assassination of former Lebanese Prime Minister Rafik Hariri. Syria had been suspected of engineering the killing, but Syrian President Bashar al-Assad denied any involvement. The report was not final, Mehlis said, but there was “evidence of both Lebanese and Syrian involvement.” Deleted, and yet uncovered by the reporters who were given the document, was an incendiary claim: that Assad’s brother Maher, commander of the Republican Guard, was personally involved in the assassination.

Microsoft Word offers a “Track Changes” option. If enabled, every change made to the document is logged as part of the document itself—but ordinarily not shown. The document bears its entire creation history: who made each change, when, and what it was. Those editing the document can also add comments—which would not appear in the final document, but may help editors explain their thinking to their colleagues as the document moves around electronically within an office. (Abelson, 2008; S.77)

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"Metadata" by Beauty and Joy of Computing by University of California, Berkeley and Education Development Center, Inc., used under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License / Desaturated from original