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#1 2018-05-20 20:54:41

atmel9077
Contributor
Registered: 2017-06-25
Posts: 38

Where do "UID writable" chips come from?

Hello

I'm asking this question because I received a few days ago some UID writeable chips that I ordered from Banggood here. (they were advertised as "Block writable" however they need the "magic command" to change the UID)

I'm wondering if a company created MIFARE chip clones specifically designed to be "UID writable", or if these are emulators based on some kind of microcontroller, or maybe a chip in which a backdoor was discovered but was only intended to be used during manufacturing.

I noticed that the block 0 ends with "bcdefghi" and by googling "mifare bcdefghi" and I found a paper from Nicolas Courtois where at page 99 he says that Kiev transport cards use Fudan microelectronics FM11RF08 and that the block 0 ends with "bcdefghi". Of course this does neither means that FM11RF08 chips are UID changeable nor that a chip which block 0 ends with "bcdefghi" is a Fudan FM11RF08, but this might be a clue concerning the source of these "UID changeable" chips. Maybe i'll order cards with FM11RF08 to see if they have the backdoor to change the UID

Last edited by atmel9077 (2018-05-20 23:47:25)


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