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  • Re: Reply To: DESFire EV1 AES. CMAC is missing from the PICC response?

    24. January 2017 at 16:24     in reply to: DESFire EV1 AES. CMAC is missing from the PICC response?

    Alex Oleon
    Reason for my problem:

    It turns out that the application 0xAAAAAA has been created with "0" keys.

    Therefore the snippet that I wrote above where the CMAC is missing could have been caused by the application being in its original state (DES) so no CMAC.


    Start from a formatted DESFire EV1 Card but with application 0 PICC key as AES key version 0x42.

    SelectApplication 0
    AuthenticateAes key 0
    GetKeyVersion R-APDU: 0x42 + CMAC + status
    GetFreeMem R-APDU: 0xF80 + CMAC + status
    CreateApplication 0x00AAAAAA, settings 0xFF, number of keys 0 R-APDU: CMAC + status
    GetApplicationIds R-APDU: 0xAAAAAA + CMAC + status
    SelectApplication 0x00AAAAAA R-APDU: status
    CreateStdDataFile file 0xf, MDCM_PLAIN, access rights 0xEEEE, file size 64 R-APDU: status + NO CMAC
    CreateBackupDataFile file 5, MDCM_PLAIN, access rights 0xEEEE, file size 64 R-APDU: status + NO CMAC
    CreateValueFile file 4, MDCM_PLAIN, access rights 0xEEEE R-APDU: status + NO CMAC
    CreateLinearRecordFile file 0, MDCM_PLAIN, access rights 0xEEEE R-APDU: status + NO CMAC
    GetFileSettings of file number 0xF R-APDU: FileSettings + status NO CMAC
    ReadData 50 bytes length, offset 0, R-APDU: 50 bytes of data + status NO CMAC

    I can see that I lost the CMAC as soon as I selected the application 0xAAAAAA that has "no key".


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