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Ntag424DNA tag issue

Question asked by long zhu on Nov 27, 2019
Latest reply on Dec 10, 2019 by long zhu

Hi,

   I'm learning the Ntag424DNA, and I get a problem as below:

  1.when I try to decrypt the SDMENCFileData (page 13th of the flie AN12196) refer to the Table4 step by step, and I can get the same data with the Table4 from the step 1 to step 15, but the last step(16), I get the different data "9254fb0561f7a8d030ee6e83487e2487" which is not same with the application note. In my understanding, the step 16 is a standard AES128 CBC arithmetic, the key is  SDMMetaReadKey ="00000000000000000000000000000000", the iv is IVe="7B3F3CFC39D3B7FF5868636E38AF7C3A", and the encrypted msg is SDMENCFileData = "94592FDE69FA06E8E3B6CA686A22842B". Therefore, the decrypted msg should be "9254fb0561f7a8d030ee6e83487e2487" rather than "78787878787878787878787878787878". Could you help me to confirm any mistake in my understanding and calculation.

  2.Leakage Resilient Primitive (LRP). We don't  kown how to achieve the LRP arithmetic even your application note AN12304 is very in detail, could you give me the demo code (source code) to achieve the LRP for our reference since we are not good at the arithmetic. Thank you very much!

Have a great day !

BR

 

Long Zhu

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