• Registered: 2010-02-08
  • Posts: 11

Topic: libnfc beginners tutorial

Hello all,

I have written an article about manipulating MiFare classic cards with libnfc and a Snapper Feeder dongle. Its a beginners tutorial along the lines of "I have a reader, so now what?", which was the situation I was in a few days ago smile

Just a question from the article: If the sector trailer has the default keys of 00 00 .. for A and FF FF ... for B, why do they seem to be reversed for the purposes of authentication, i.e I can authenticate with FF FF for A but not 00 00 ? Dodgy card?

The article is here

  • rconty
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  • Registered: 2009-04-22
  • Posts: 642

Re: libnfc beginners tutorial

mcbridematt wrote:

Hello all,

I have written an article about manipulating MiFare classic cards with libnfc and a Snapper Feeder dongle. Its a beginners tutorial along the lines of "I have a reader, so now what?", which was the situation I was in a few days ago smile

Great ! If you want to goes deeper in MIFARE manipulation, you should be interresting in libfreefare from nfc-tools project.

mcbridematt wrote:

Just a question from the article: If the sector trailer has the default keys of 00 00 .. for A and FF FF ... for B, why do they seem to be reversed for the purposes of authentication, i.e I can authenticate with FF FF for A but not 00 00 ? Dodgy card?

I don't understand exactly what happends to you... maybe related to access bits ?

If you want more, could you describe better the case ? With dump and examples ?

Romuald Conty
  • rsei
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  • Registered: 2010-11-04
  • Posts: 1

Re: libnfc beginners tutorial

mcbridematt wrote:

Just a question from the article: If the sector trailer has the default keys of 00 00 .. for A and FF FF ... for B, why do they seem to be reversed for the purposes of authentication, i.e I can authenticate with FF FF for A but not 00 00 ? Dodgy card?

Actually both default keys of your MIFARE classic card are "FFFFFFFFFFFF". However key A can't be read, so the output of key A will show all zeroes.