ChangeKey and Error Code 1E.

Forum / MIFARE general topics and applications / ChangeKey and Error Code 1E.

  • 16. March 2016 at 16:21

    Warren Ashman
    Hi,

    Is this the right forum for help with C# applications that communicate with the Mifare DESFire chip? I have a problem getting ChangeKey (0xC4) to work and get response 0x1E.

    I need to change the Application Master Key. I am authenticating with the AMK and attempting to change it's value.

    Steps:
    Select application and authenticated using the existing single DES AMK.
    Calculating CRC16 of the new double DES AMK.
    Appending CRC16 to new key and padding with six zero bytes to get data ready for encrypting (24 bytes).
    Single DES CBC decrypt with session key and send using command 0xC4.

    I guess the problem is with the CRC16, but I have tried several different algorithms without success.

    Can any one advise me where I am going wrong. I have no problems with any of the other commands, its just ChangeKey that does not work.


    Thanks,

    Warren

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    Re: ChangeKey and Error Code 1E.

    17. March 2016 at 12:12

    mifaresdk
    Hi Warren,

    The error code 0x1E is “Integrity Error” and means that the CRC or the MAC does not match to the data or the padding bytes are not valid.

    For deeper analysis it is difficult or impossible to make a statement when you do not know what the unknown framework does.

    Please have also a look to this post:

    https://www.mifare.net/support/forum/topic/change-key/

    Here I have checked the ChangeKey command with a tool.

    The MIFARE Team
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    Re: ChangeKey and Error Code 1E.

    17. March 2016 at 14:54

    Warren Ashman
    Hi,

    I am communicating directly with the card via Scard api for Windows, no framework used. I need to know the specification for the ChangeKey command and the CRC algorithm used.
    I have the specification for MF31C40, but actually have a MF3ICD81 EV1. How do I get hold of the following specification: MF3ICD81 MIFARE DESFire EV1_3.6?

    Regards,

    Warren
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    Re: ChangeKey and Error Code 1E.

    1. April 2016 at 11:05

    mifaresdk
    Hi Warren,

    The MF3ICD81 is the technical description for the MIFARE DESFire EV1 and the MF3ICD40 is it for the (legacy) MIFARE DESFire. The full datasheet with all details of native commands is NDA classified. You can get it from your local NXP representative office.

    http://www.nxp.com/about/worldwide-locations:GLOBAL_SITES


    Kind regards,
    The MIFARE Team
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