Hidden Data in NFC Tags
I've just got a set of wearable NFC tags, and I've discovered something interesting about the way data is stored on them. tl;dr Overwriting a tag can leave old data intact, and still readable. Here's the decoded memory layout of a tag with data written to it. In this case, a (failed) experiment at storing a JavaScript pop-up. # NDEF message: [00] D1 01 7D 55 00 64 61 74 61 3A 74 65 78 74 2F 68 |.␁}U␀data:text/h| [10] 74 6D 6C 3B 63 68 61 72 73 65 74 3D 75 74 66 2D |tml;charset=utf-| [20] 38 2…
Continue reading →