Reply To: Error E1 when changekey from TDES to AES on Desfire Card

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Re: Error E1 when changekey from TDES to AES on Desfire Card

19. May 2023 at 9:55
Answer to myself, with the very good help from NXP support team: my card was initialized in single DES, and I computed the session as if it was not.

The good computation is explained at the bottom of 6.2 p. 45 or the doc AN0945:
- session key = RndA(byte0-byte3) + RndB(byte0-byte3)
and, in my case, not RndA(byte0-byte3) + RndB(byte0-byte3) + RndA(byte4-byte7) + RndB(byte4-byte7)

That's all, and simple.
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