Authentication Mifare Classic

Forum / MIFARE and NFC Reader IC`s / Authentication Mifare Classic

  • 19. March 2020 at 16:57
    Hi All,

    I'm currently trying to read/write data from my mifare classic card.
    I see a lot of examples pointing to the NXP library only that one is to large for my embedded environment, so i want to create my own functions.

    Currently I'm able to detect and read the UID from the card.
    Next step is to read a data block.

    In the datasheet for the Mifare Classic, I see that in order to read/write data you first need to authentication to a sector block.
    This is done in three steps:
    1. send authorization request for data sector 0, 0x60 - 0x00 - CRC
    2. As response 4 token bytes are received, token RB.
    3. Send 8 byte token to the Card, token AB
    4. Receive 4 byte token for validation, token BA

    I have got it to step 2, so I receive the 4 bytes token (token RB). but I have no clue on how to calculate the 8 bytes return data?
    Could someone explain to me on how to calculate token AB.

    Kind regards,
    Peter

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    Re: Authentication Mifare Classic

    23. March 2020 at 9:49
    Hi Peter,

    First of all: you need a NXP NFC reader chip for reading and writing of a MIFARE Classic. The reason is the proprietary cipher of the MIFARE Classic. The authentication is implemented in every NXP NFC reader. Usually you store the keys (A and/or B) in the registers of the reader and execute the authentication.

    The TapLinx team

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    Re: Authentication Mifare Classic

    23. March 2020 at 11:50
    Hi,

    Thank you for your quick response.

    I currently use the PN512 for the detection of the card.
    So if I understand you correctly I need to store the keys to the dedicated registers in the chip and then it will do the encryption for me?

    I will try to send the keys to the registers and then send the authentication command.

    Kind regards,
    Peter
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    Re: Authentication Mifare Classic

    24. March 2020 at 9:14
    Hi Peter,

    If you write to me at: taplinx@nxp.com, I can offer how to write to the PN512 FIFO for communicating with the MIFARE Classic.

    The TapLinx team
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