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Mifare - Crypto1 - Cipher initialization

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axxe

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Hi!

im trying to complete a Mifare authentication with a 8bit microcontroller.
I've found this log with either encrypted and unencrypted nonces:
key: FF FF FF FF FF FF
UID: 2a 69 8d 43
nT: 3b ae 03 2d
nR+aR: bb 03 1f 2d 7f cf 34 c3
{nR}+{aR}: c4! 94 a1 d2 6e! 96 86! 42
aT: 86 9d bb d5
{aT}: 84 66! 05! 9e!
My first step is to get the same {nR} knowing the nR, the UID and the key
I've already successfully calculated the aR and aT starting from the tag nonce. Now im trying to crypting them.
As I said im using an 8bit microcontroller so i cant even use an unique 48bit or 64bit variable but im trying to avoid this problem.
Anyone may give me some hints how to initialize the cipher step by step focusing also on the bit orientation (LSB/MSB) ?
this is what i've done:
-I've started to set up the cipher with the 48bit key (FF FF FF FF FF FF).
-I've added the nT and the UID shifting the cipher for each of the 32bits adding the new bit on the right
-adding the nR im filling up the {nR}
but i dont get expected results of course...
may somebody helps me? ThanKs!

It would be helpfull for me even to know some logs of the cipher initialization process.
for example I would like to see the state of the 48bit cipher after filling it with the nT and the UID (after the first 32clocks) knowing the key, the UID and the tag Nonce.
Then i would be able to check if my currently work is ok or no.


sorry for my english and for my newbie questions

-AxxE-
 

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