title: Mifare 1k what is the use of two keys
body: <p>Why are there two keys available (key A and B) for every sector in Mifare 1k smart card?
  I have read the documentation and I can't find any explanation on the use of two keys. Why they didn't put one 12 byte key instead of two 6 byte keys?
  The only logical explanation, to me, is to have one master key(A), with which you can change the other key(B), and use the other key(B) for authentication and read/write operations.
  So for example, one person can have the B key, and can write and read data blocks from the card, but can't change neither the A or B key, or access codes.</p>
  
  <p>I'm I anywhere near?</p>
  
  <p>Tnx guys</p>