SAM Master key change to PICC type after switch to AV2 mode

[Jesús Manuel Gómez Fernández]

Hi,

I'm integrating the MIFARE SAM AV2 in our system, and I've got to set the SAM Master key as PICC key type after switching to AV2 mode. Because of that, now I don´t authenticate with SAM Master key, an execute other command.

SAM_ChangeKeyEntryAV2 -->
2017/07/14; 13:33:58.804. Command Apdu:
80 C1 00 FF 3D 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 FF F0 01 00 00 00 FF 20 00 00 00
00 11
2017/07/14; 13:33:59.038. Response APDU:
90 00

Is there a solution to change again the key type of SAM MAster key to AES-128?

Thanks in advanced

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[TapLinx Support]

Hi Jesús Manuel,


You can change any key if you are able to make a Host Authentication before. The command depends of the type of key e.g.: Host key, Offline Change key, Offline Crypto key or PICC key. Please read the description in the datasheet 11.2.2.1 SAM_ChangeKeyEntry and SAM_ChangeKUCEntry.

The TapLinx team

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[Jesús Manuel Gómez Fernández]

Hi,

I know what you say. My problem os that the only key enable is the SAM Master key, and now that key is PICC type, and the autentications with SAM Master key return 6985.
What is the solution?

Thanks in advanced.

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[TapLinx Support]

Now I understand your issue. You changed the type of key from Host Key to PICC Key. But to make another key to a Host Key, you need to make a host authentication first (which is not possible, because the previous Host Key is a PICC Key now).

I will try to talk with a “SAM expert” and come back with an answer.

The TapLinx team

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[TapLinx Support]

Hi Jesús Manuel,

Sorry for the long delay.

Unfortunately I have bad news for you. If you invalidate the Host Key, you cannot make another key to a Host key without a host authentication. Otherwise it breaks the security of the SAM AV2.

Sorry,
The TapLinx team

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